Sildenafil increases oxygen delivery and maximal exercise capacity at very high altitudes (greater than or equal to 4300 m) and has been shown to improve short-duration exercise performance in some individuals at simulated high altitude (3900 m). It is unknown whether sildenafil improves maximal exercise capacity and longer duration exercise performance at moderate and high altitudes where competitions are more common. Additionally, the effects of sildenafil on women exercising at altitude have not been examined. The purpose of this study was to determine the effects of sildenafil on cardiovascular hemodynamics, arterial oxygen saturation (SaO2), peak exercise capacity (Wpeak), and 15-km time trial performance, in endurance-trained men and women at simulated moderate (MA; 2100 m, 16.2 % FIO2) and high (HA; 3900 m, 12.8% FIO2) altitudes. Eleven male and 10 female subjects completed two HA Wpeak trials following the ingestion of placebo or 50 mg sildenafil in randomized, counterbalanced, and double blind fashion. Subjects then completed four exercise trials (30 min at 55% of Wpeak + 15-km time trial) at MA and HA following the ingestion of placebo or 50 mg sildenafil in randomized, counterbalanced, and double blind fashion. Sildenafil had little influence on cardiovascular hemodynamics for either gender at MA or HA, but did result in higher SaO2 values compared to placebo during steady state and time trial exercise in men at HA only. Sildenafil did not affect Wpeak or 15-km time trial performance in either gender at MA or HA. We conclude that sildenafil is unlikely to exert beneficial effects at altitudes < 4000 m for a majority of the population.

Estudos para obter perfis químicos ou físicos de drogas ilícitas destinam-se a provar materialmente a existência de um crime ou para fornecer informações precisas aos serviços de inteligência estratégica e operacional. Um perfil pode ser definido como um conjunto de características específicas selecionadas para proporcionar informações sobre determinada produção, por exemplo, clandestina. Historicamente, focados sobre drogas de abuso, tais estudos podem ser perfeitamente utilizados em outro problema das Ciências Forenses: a falsificação de medicamentos. Seguindo uma tendência mundial, a maior incidência de medicamentos falsificados no Brasil é dos produtos Viagra® (citrato de sildenafila, SLD, Pfizer) e Cialis® (tadalafila, TAD, Eli Lilly). Avaliaram-se perfis físicos e químicos de amostras forenses de Viagra e Cialis falsificados fazendo uso de Análise Multivariada de Dados (AMD). O controle físico dos comprimidos, o perfil inorgânico por espectrometria de fluorescência de raios – X (XRF), o perfil orgânico por espectrometria de massa com ionização por eletro spray (ESI-MS), o perfil de ingredientes farmacologicamente ativos (IFA) por cromatografia líquida acoplada espectrometria de massa (UPLC-MS) e o perfil por espectroscopia de infravermelho (FTIR-ATR) foram avaliados para caracterizar as amostras, detectando falsificações e agrupando amostras com propriedades semelhantes. Os resultados mostraram a presença de falsificações de risco à saúde com a existência de outros IFA do que o especificado na embalagem; a ocorrência simultânea de dois IFA em um mesmo produto; a existência de outros IFA (contaminantes); e concentrações de TAD e SLD muito mais elevadas do que nos medicamentos originais. A aplicação de ferramenta de AMD torna a representação dos dados experimentais mais clara e conclusiva relativamente às diferenças na composição das amostras testadas. Identificamos pares de amostras de apreensões diferentes estreitamente ligadas pelo perfil químico, que podem estar associadas a uma origem ilícita comum de mistura farmacêutica pré-compressão e/ou de ciclo de compressão. Além disso, nossos resultados sugerem a hipótese de uma mesma mistura farmacêutica, contendo apenas SLD, foi empregada na fabricação de comprimidos falsificados de Viagra e de Cialis. / Studies to obtain chemical or physical profiles of illicit drugs intended to materially prove the existence of a crime or to provide to accurate information the strategic and operational intelligence services. A profile can be defined as a series of specific characteristics selected to provide information about certain production (e.g., clandestine). Historically focused on drugs of abuse, such studies can be perfectly used in another problem on Forensic Sciences field: counterfeit medicines. Following a global trend, the highest incidence of counterfeit medicines in Brazil is on the products Viagra® (sildenafil citrate, SLD, Pfizer) and Cialis® (tadalafil, TAD, Eli Lilly). We studied physical and chemical profiles of forensic counterfeit Viagra and Cialis samples using also Multivariate Data Analysis (MDA). Physical control of tablets, inorganic profile by X – Ray fluorescence spectrometry (XRF), organic profile by electrospray ionization mass spectrometry (ESI-MS), active pharmacologically ingredients (API) profile by liquid chromatography coupled mass spectrometer (UPLC-MS) and infrared spectroscopy (FTIR-ATR) profiles were evaluated to characterize the samples allowing detection of counterfeits and grouping samples with similar properties. The results showed the presence of health risk counterfeits with the existence of API other than specified on the package, the simultaneous occurrence of two API in the same product, the existence of others contaminants API and concentrations of TAD and SLD much higher than in original commercial tablets. By applying a MDA tool the experimental data representation becomes more clear and conclusive with respect to the differences in composition of tested samples. We identified paired samples from different seizures closely linked by chemical profile, which can be associated with a common origin of mixture powders and/or tableting cycle. In addition, our results suggest the hypothesis of a unique pharmaceutical powder mixture containing only SLD, which was compressed into counterfeits Viagra and Cialis tablets.

Estudos para obter perfis químicos ou físicos de drogas ilícitas destinam-se a provar materialmente a existência de um crime ou para fornecer informações precisas aos serviços de inteligência estratégica e operacional. Um perfil pode ser definido como um conjunto de características específicas selecionadas para proporcionar informações sobre determinada produção, por exemplo, clandestina. Historicamente, focados sobre drogas de abuso, tais estudos podem ser perfeitamente utilizados em outro problema das Ciências Forenses: a falsificação de medicamentos. Seguindo uma tendência mundial, a maior incidência de medicamentos falsificados no Brasil é dos produtos Viagra® (citrato de sildenafila, SLD, Pfizer) e Cialis® (tadalafila, TAD, Eli Lilly). Avaliaram-se perfis físicos e químicos de amostras forenses de Viagra e Cialis falsificados fazendo uso de Análise Multivariada de Dados (AMD). O controle físico dos comprimidos, o perfil inorgânico por espectrometria de fluorescência de raios – X (XRF), o perfil orgânico por espectrometria de massa com ionização por eletro spray (ESI-MS), o perfil de ingredientes farmacologicamente ativos (IFA) por cromatografia líquida acoplada espectrometria de massa (UPLC-MS) e o perfil por espectroscopia de infravermelho (FTIR-ATR) foram avaliados para caracterizar as amostras, detectando falsificações e agrupando amostras com propriedades semelhantes. Os resultados mostraram a presença de falsificações de risco à saúde com a existência de outros IFA do que o especificado na embalagem; a ocorrência simultânea de dois IFA em um mesmo produto; a existência de outros IFA (contaminantes); e concentrações de TAD e SLD muito mais elevadas do que nos medicamentos originais. A aplicação de ferramenta de AMD torna a representação dos dados experimentais mais clara e conclusiva relativamente às diferenças na composição das amostras testadas. Identificamos pares de amostras de apreensões diferentes estreitamente ligadas pelo perfil químico, que podem estar associadas a uma origem ilícita comum de mistura farmacêutica pré-compressão e/ou de ciclo de compressão. Além disso, nossos resultados sugerem a hipótese de uma mesma mistura farmacêutica, contendo apenas SLD, foi empregada na fabricação de comprimidos falsificados de Viagra e de Cialis. / Studies to obtain chemical or physical profiles of illicit drugs intended to materially prove the existence of a crime or to provide to accurate information the strategic and operational intelligence services. A profile can be defined as a series of specific characteristics selected to provide information about certain production (e.g., clandestine). Historically focused on drugs of abuse, such studies can be perfectly used in another problem on Forensic Sciences field: counterfeit medicines. Following a global trend, the highest incidence of counterfeit medicines in Brazil is on the products Viagra® (sildenafil citrate, SLD, Pfizer) and Cialis® (tadalafil, TAD, Eli Lilly). We studied physical and chemical profiles of forensic counterfeit Viagra and Cialis samples using also Multivariate Data Analysis (MDA). Physical control of tablets, inorganic profile by X – Ray fluorescence spectrometry (XRF), organic profile by electrospray ionization mass spectrometry (ESI-MS), active pharmacologically ingredients (API) profile by liquid chromatography coupled mass spectrometer (UPLC-MS) and infrared spectroscopy (FTIR-ATR) profiles were evaluated to characterize the samples allowing detection of counterfeits and grouping samples with similar properties. The results showed the presence of health risk counterfeits with the existence of API other than specified on the package, the simultaneous occurrence of two API in the same product, the existence of others contaminants API and concentrations of TAD and SLD much higher than in original commercial tablets. By applying a MDA tool the experimental data representation becomes more clear and conclusive with respect to the differences in composition of tested samples. We identified paired samples from different seizures closely linked by chemical profile, which can be associated with a common origin of mixture powders and/or tableting cycle. In addition, our results suggest the hypothesis of a unique pharmaceutical powder mixture containing only SLD, which was compressed into counterfeits Viagra and Cialis tablets.

Estudos para obter perfis químicos ou físicos de drogas ilícitas destinam-se a provar materialmente a existência de um crime ou para fornecer informações precisas aos serviços de inteligência estratégica e operacional. Um perfil pode ser definido como um conjunto de características específicas selecionadas para proporcionar informações sobre determinada produção, por exemplo, clandestina. Historicamente, focados sobre drogas de abuso, tais estudos podem ser perfeitamente utilizados em outro problema das Ciências Forenses: a falsificação de medicamentos. Seguindo uma tendência mundial, a maior incidência de medicamentos falsificados no Brasil é dos produtos Viagra® (citrato de sildenafila, SLD, Pfizer) e Cialis® (tadalafila, TAD, Eli Lilly). Avaliaram-se perfis físicos e químicos de amostras forenses de Viagra e Cialis falsificados fazendo uso de Análise Multivariada de Dados (AMD). O controle físico dos comprimidos, o perfil inorgânico por espectrometria de fluorescência de raios – X (XRF), o perfil orgânico por espectrometria de massa com ionização por eletro spray (ESI-MS), o perfil de ingredientes farmacologicamente ativos (IFA) por cromatografia líquida acoplada espectrometria de massa (UPLC-MS) e o perfil por espectroscopia de infravermelho (FTIR-ATR) foram avaliados para caracterizar as amostras, detectando falsificações e agrupando amostras com propriedades semelhantes. Os resultados mostraram a presença de falsificações de risco à saúde com a existência de outros IFA do que o especificado na embalagem; a ocorrência simultânea de dois IFA em um mesmo produto; a existência de outros IFA (contaminantes); e concentrações de TAD e SLD muito mais elevadas do que nos medicamentos originais. A aplicação de ferramenta de AMD torna a representação dos dados experimentais mais clara e conclusiva relativamente às diferenças na composição das amostras testadas. Identificamos pares de amostras de apreensões diferentes estreitamente ligadas pelo perfil químico, que podem estar associadas a uma origem ilícita comum de mistura farmacêutica pré-compressão e/ou de ciclo de compressão. Além disso, nossos resultados sugerem a hipótese de uma mesma mistura farmacêutica, contendo apenas SLD, foi empregada na fabricação de comprimidos falsificados de Viagra e de Cialis. / Studies to obtain chemical or physical profiles of illicit drugs intended to materially prove the existence of a crime or to provide to accurate information the strategic and operational intelligence services. A profile can be defined as a series of specific characteristics selected to provide information about certain production (e.g., clandestine). Historically focused on drugs of abuse, such studies can be perfectly used in another problem on Forensic Sciences field: counterfeit medicines. Following a global trend, the highest incidence of counterfeit medicines in Brazil is on the products Viagra® (sildenafil citrate, SLD, Pfizer) and Cialis® (tadalafil, TAD, Eli Lilly). We studied physical and chemical profiles of forensic counterfeit Viagra and Cialis samples using also Multivariate Data Analysis (MDA). Physical control of tablets, inorganic profile by X – Ray fluorescence spectrometry (XRF), organic profile by electrospray ionization mass spectrometry (ESI-MS), active pharmacologically ingredients (API) profile by liquid chromatography coupled mass spectrometer (UPLC-MS) and infrared spectroscopy (FTIR-ATR) profiles were evaluated to characterize the samples allowing detection of counterfeits and grouping samples with similar properties. The results showed the presence of health risk counterfeits with the existence of API other than specified on the package, the simultaneous occurrence of two API in the same product, the existence of others contaminants API and concentrations of TAD and SLD much higher than in original commercial tablets. By applying a MDA tool the experimental data representation becomes more clear and conclusive with respect to the differences in composition of tested samples. We identified paired samples from different seizures closely linked by chemical profile, which can be associated with a common origin of mixture powders and/or tableting cycle. In addition, our results suggest the hypothesis of a unique pharmaceutical powder mixture containing only SLD, which was compressed into counterfeits Viagra and Cialis tablets.

Recent studies have shown that the potent phosphodiesterase-5 (PDE-5) inhibitor, sildenafil citrate, induces a powerful cardioprotective effect against ischemia-reperfusion (I/R) injury in rabbit and mouse hearts. However, the effect of this drug in inducing long-term protection against I/R injury remains unknown. The goal of this study was to identify the duration of the protective window of sildenafil citrate as well as vardenafil, a more potent PDE-5 inhibitor. Rabbits were treated with sildenafil (0.7 mg/kg, iv), vardenafil (0.143 mg/kg), or an equivalent volume of saline. After 24 hrs, 48 hrs, 96 hrs, or 7 days of sildenafil treatment, the hearts were subjected to I/R. In the vardenafil groups, the hearts were subjected to I/R at 24 hrs and 7 days after administration of the drug. To evaluate the role of nitric oxide (NO) in cardioprotection, a non-selective blocker of nitric oxide synthase, L-NAME (15 mg/kg, iv) was administered 10 minutes prior to I/R. The results show significant reductions in infarct size in hearts treated with sildenafil and vardenafil as compared to the corresponding saline controls at all time points. The protective effects of sildenafil and vardenafil were abrogated in animals treated with L-NAME. L-NAME had no effect on infarct size in saline treated control rabbits. These data suggest that both sildenafil and vardenafil induce a long-term protective effect against myocardial infarction which is mediated via a NO-dependent pathway. These studies are important in exploiting the clinical potential of PDE-5 inhibitors in terms of protection against ischemia/reperfusion injury in patients with coronary artery disease.

La publicité directe des médicaments d’ordonnance (PDMO), interdite au Canada, influence la relation tripartite entre l’industrie pharmaceutique, les consommateurs de médicaments d’ordonnance et les professionnels de la santé. L’industrie pharmaceutique, un secteur très lucratif, emploie diverses tactiques publicitaires dont plusieurs sont nuisibles aux consommateurs. Ces derniers sont la cible de la PDMO et interprètent de multiples façons le message publicitaire reçu. Finalement, les professionnels de la santé jouent un rôle crucial entre l’industrie et les consommateurs puisqu’une ordonnance est nécessaire pour se procurer le produit publicisé. L’encadrement normatif visant la PDMO au Canada est de sources variées. La législation mentionne clairement l’interdiction de ce type de publicité, mais Santé Canada tolère tout de même deux usages relatifs à la PDMO : les annonces de rappel de marque et les annonces de recherche d’aide. Cette situation crée de la confusion puisque l’information transmise aux consommateurs est incomplète. Les Américains ont légalisé la PDMO en favorisant son potentiel éducatif. Il est toutefois difficile de constater les effets positifs de cette légalisation sur la santé publique et l’économie américaine. Au Canada, le médicament Viagra a été l’objet de PDMO, lui conférant un succès économique et populaire. Mais cette notoriété fait que les consommateurs associent aisément le produit à la condition qu’il traite, ce qui est contraire aux usages tolérés par Santé Canada. Tous ces éléments renforcent notre position quant à l’importance de maintenir l’interdiction législative de la PDMO et de l’appliquer de manière plus rigoureuse. / Direct-to-consumer-advertising of prescription drugs (DTCAPD), forbidden in Canada, influences the three-way relationship between the pharmaceutical industry, the consumers of prescription drugs and the health care professionals. The pharmaceutical industry, a very profitable business, uses different advertising tactics that can be detrimental to the consumers. The consumers are the target of DTCAPD and interpret in many ways the advertising messages that are being sent. Finally the health care professionals are playing a crucial role between the industry and the consumers as prescriptions are necessary in order to receive the advertised drugs. The Canadian normative framework surrounding DTCAPD has different sources. The legislation is clearly forbidding these advertisements, but Health Canada is still permitting two types of messages: Reminder Ads and Help-Seeking Messages. This situation is confusing since the transmitted information is generally incomplete. The United-States legalised DTCAPD for its educational potential. It is yet difficult to observe the positive effects on the public health and the economy of this country. In Canada, the prescription drug Viagra was the target of DTCAPD and was an economical and popular success. This recognition however helps the consumers to associate the drug and the condition it is treating, which is contrary to the exception framework set up by Health Canada. All these elements strengthen our position to maintain the DTCAPD legislative interdiction and to apply it in a rigorous manner.

La publicité directe des médicaments d’ordonnance (PDMO), interdite au Canada, influence la relation tripartite entre l’industrie pharmaceutique, les consommateurs de médicaments d’ordonnance et les professionnels de la santé. L’industrie pharmaceutique, un secteur très lucratif, emploie diverses tactiques publicitaires dont plusieurs sont nuisibles aux consommateurs. Ces derniers sont la cible de la PDMO et interprètent de multiples façons le message publicitaire reçu. Finalement, les professionnels de la santé jouent un rôle crucial entre l’industrie et les consommateurs puisqu’une ordonnance est nécessaire pour se procurer le produit publicisé. L’encadrement normatif visant la PDMO au Canada est de sources variées. La législation mentionne clairement l’interdiction de ce type de publicité, mais Santé Canada tolère tout de même deux usages relatifs à la PDMO : les annonces de rappel de marque et les annonces de recherche d’aide. Cette situation crée de la confusion puisque l’information transmise aux consommateurs est incomplète. Les Américains ont légalisé la PDMO en favorisant son potentiel éducatif. Il est toutefois difficile de constater les effets positifs de cette légalisation sur la santé publique et l’économie américaine. Au Canada, le médicament Viagra a été l’objet de PDMO, lui conférant un succès économique et populaire. Mais cette notoriété fait que les consommateurs associent aisément le produit à la condition qu’il traite, ce qui est contraire aux usages tolérés par Santé Canada. Tous ces éléments renforcent notre position quant à l’importance de maintenir l’interdiction législative de la PDMO et de l’appliquer de manière plus rigoureuse. / Direct-to-consumer-advertising of prescription drugs (DTCAPD), forbidden in Canada, influences the three-way relationship between the pharmaceutical industry, the consumers of prescription drugs and the health care professionals. The pharmaceutical industry, a very profitable business, uses different advertising tactics that can be detrimental to the consumers. The consumers are the target of DTCAPD and interpret in many ways the advertising messages that are being sent. Finally the health care professionals are playing a crucial role between the industry and the consumers as prescriptions are necessary in order to receive the advertised drugs. The Canadian normative framework surrounding DTCAPD has different sources. The legislation is clearly forbidding these advertisements, but Health Canada is still permitting two types of messages: Reminder Ads and Help-Seeking Messages. This situation is confusing since the transmitted information is generally incomplete. The United-States legalised DTCAPD for its educational potential. It is yet difficult to observe the positive effects on the public health and the economy of this country. In Canada, the prescription drug Viagra was the target of DTCAPD and was an economical and popular success. This recognition however helps the consumers to associate the drug and the condition it is treating, which is contrary to the exception framework set up by Health Canada. All these elements strengthen our position to maintain the DTCAPD legislative interdiction and to apply it in a rigorous manner.

Men who have sex with men (MSM) account for a majority of all men currently diagnosed with AIDS. MSM is also recognized as the largest risk category of all AIDS cases. Drug use has been shown to have a synergistic effect on the prevalence of HIV in the MSM population. The study aimed to examine the association between injection drug use, non-injection drug use, and non-drug use with sexual risk behaviors for HIV in men who have sex with men. Secondary, cross-sectional data procured from the National HIV Behavioral Surveillance System for the Atlanta Metropolitan Survey Area were used for the study. The study population was 960 participants. Using binary logistic regression analyses, the drug use categories were studied for unprotected intercourse, unprotected receptive anal intercourse and HIV status. Strong associations were seen independently for unprotected intercourse, unprotected receptive anal intercourse, and HIV status with injection and non injection drug use, but the association weakened for drug use categories when controlled for other independent factors. Taking into account current findings and findings from previous research, the importance of clinical significance over statistical significance was considered. Racial disparities were evident, in that, although the Black participants showed no increased odds for sexual risk factors or drug use, it had a higher odds for being HIV positive compared to Whites. Combining Viagra/Levitra with drugs was significantly associated with unprotected intercourse (AOR=1.9), and each individual drug showed a different degree of association with Viagra/Levitra. Further research is recommended to identify sub-populations at risk and appropriately allocate resources and channel programs and interventions.

Världsmarknaden för läkemedlen beräknades år 2011 till 900 miljarder US$ enligt IMS-health. Marknaden för illegala läkemedel uppskattas vara värd mellan 75-200 miljarder dollar. I Sverige uppskattas den illegala läkemedelsmarknaden till motsvarande ≤0,5 %. Straffet för insmuggling av läkemedel till Sverige är böter eller max 2 års fängelse. Tullverket räknar med att man endast hittar 10 % av det som smugglas in. I andra länder kan straffet variera mellan böter (ekonomisk brottslighet i Afrika) till dödsstraff i Kina. I Utvecklingsländerna uppskattas 10-30 % av alla läkemedel som säljs vara förfalskade, jmf 1 % I-länderna. l. Förekomsten av förfalskade läkemedel har många allvarliga konsekvenser på människor som exempelvis, utebliven effekt, toxiska reaktioner, förgiftningar, som kan i värsta fall leda till döden. Ett annat alvarligt problem är resistensutveckling, ökad spridning av smittsamammasjukdomar som exempel, tuberkulos och/ eller HIV/AIDS. Syftet med detta examensarbete är att besvara frågan: Vilka problem ger den ökande förekomsten av förfalskade läkemedel i samhället. Undersökningen fokuserar på livstidsläkemedel, dvs ett läkemedel en person måste ta resten av sitt liv för behandling av sin kroniska sjukdom. För att komma till rätta med de problem, som förfalskade läkemedel, skapar krävs ett mer utvecklat samarbete mellan olika läkemedelsmyndigheter, läkemedelsföretag, internationella polisorganisationer, tull m.fl. Arbetet med att utveckla förpackningar som är svåra att förfalska bör intensifieras. Straffsatser bör kanske ses över. Det är viktigt att öka medvetandet bland allmänheten om risker med att köpa läkemedel utanför apotek (t ex via nätet).

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / We evaluated the effect of sildenafil citrate (ViagraÂ) a vasodilator largely used for the treatment of male erectile dysfunction, on the gastrointestinal motility in rats. Experiments were performed on 175 male, Wistar rats, weighing 200-350g. Four groups of study were done: the sildenafil effects on the: i) Gastric emptying (GE) and gastrointestinal (GI) transit and ii) Intestinal transit (IT) of liquid in awake rats; iii) Gastric compliance in anesthetized rats and iv) Contractility of rat duodenal isolated strips. i) In 64 rats fasted for 24h with previous vascular access (right jugular vein and left carotid artery), we studied the effect of an i.v. injection (0.2mL) of sildenafil (4mg/Kg) or vehicle (0.01N HCl) on GE and GI transit of a liquid meal, as well as on arterial pressure (AP) in a separated group of rats. Animals were gavage-fed with 1.5mL of a test meal (0.5mg/mL of phenol red in 5% glucose). After 10, 20 or 30min, animals were sacrificed and submitted to a laparotomy to obstruct the pylorus, cardia and terminal ileus. The gut was removed and then divided into: stomach and consecutive three small intestine segments (40% proximal; 30% medial and 30% terminal). After processing these segments, the dye retention was determined at 560nm. The percentage of dye retention in each segment permitted to evaluate GE and GI transit. Arterial pressure was continuously monitored by a digital acquisition system during 20min before and 30min after sildenafil injection. We observed a significant increase of gastric retention in sildenafil treated rats at 10, 20, or 30min after the test meal (44,2Â2,0 vs 53,2Â2,1; 25,4Â1,3 vs 37,3Â1,6; 20,9Â2,5 vs 32,5Â2,9%, respectively), as well as a significant GI transit delay. Despite of sildenafil inducing hypotension, AP returned to basal levels 10min afterwards. Acid gastic secretion blocking pre-treatment with omeprazol did not modify the sildenafil effect on gastric retention, GI transit or AP. ii) In another group we evaluated the sildenafil (4mg/Kg) or diluente (0.01N HCl, 0.2mL) effects on the IT in awake rats, fasted for 24h. Animals were studied 3d after the insertion of a silastic cannula (0.6cm ID) into the duodenal bulb. We evaluated the progression of a radioactive liquid test meal fed (10MBq of 99mTc â 1mL of saline 0,9%) administered through the inserted cannula into the small intestine. After 20, 30 or 40min, animals were sacrificed by anesthetic overdose. After laparotomy, we removed and divided the gut in: stomach, five congruent and consecutive segments of the small intestine and the large intestine. Radioactivity counting was obtained in a gamma-chamber collimator. Sildenafil promoted an IT delay (p<0.05), indicated by shifting the center of mass to the proximal portions of the TGI (2.8Â0.2 vs 3.3Â0.1; 3.0Â0.2 vs 3.7Â0.1 and 3.4Â0.1 vs 4.2Â0.2) in relation to control group. iii) Gastric compliance study was performed on 39 anesthetized rats after 24h of fasting. Gastric volume (GV) variations were measured by plethysmography while AP was continuously monitored. We have also observed that GV increased (p<0.05) after sildenafil treatment (3mg/Kg - e.v) (3.08Â0.18; 3.10Â0.17 and 3.09Â0.17mL vs 2.91Â0.19mL) at 10, 20 and 30min after drug administation, respectively. Basal AP (105.8Â2.28mmHg) dropped by the sildenafil injection (59.8Â3.2; 64.8Â3.7 and 59.3Â4.6mmHg-p<0.05) while vehicule (0.01N HCl) did not change either GV or AP. After splanchnotomy or pre-treatments (e.v.) with methylene blue (3mg/Kg-guanilate cyclase blocker), L-NNA (3mg/Kg - NO synthase blocker) or propranolol (2mg/Kg - Ã-blocker) prevented GV increase due to sildenafil; while post-treatment with sodium nitroprusside (1mg/Kg - NO donor) raised it. iv) The in vitro contractility studies were performed on isolated duodenal strips obtained from rats (n=28) killed by cervical dislocation. Duodenal strips were suspended longitudinally in a glass chamber (10mL), filled with Tyrode solution (37oC and pH 7.4). After 1h of stabilization under 1g of initial tension, the spontaneous or induced contractility were continuously recorded by a digital acquisition system. Increasing and cummulative doses of sildenafil (0.1 to 300Âmol/L) relaxed (9.6Âmol/L of EC50) the duodenal strips. This effect was more intense than those displayed by zaprinast or papaverine (PDEs blockers) (91.6 and 78.5Âmol/L of EC50, in this order). Sildenafil showed significant antispasmodic and myorelaxant effects on the duodenal contractions induced by acetylcholine or carbamylcholine (IC50 26.7 and 16.2Âmol/L, respectively). Pre-treatment with methylene blue, ODQ (guanilato cyclase blocker) or L-NAME (NO synthase blocker) also prevented these sildenafil effects, but D-NAME (an inactive substrate for NO synthase) did not. Myorelaxant sildenafil effect was reverted by L-arginine (substrate for NO synthase) and contrarily it was largely increased by sodium nitroprusside. Forskolin adenylate cyclase activation pre-treatment also increased the myorelaxant effect of sildenafil. In summary, we have observed that sildenafil slowed down the gastrointestinal motility, delaying GE, GI and intestinal transits of a liquid meal in awake rats; Gastric compliance was also increased in anesthetized rats treated with sildenafil. Sildenafil also exhibited both antispasmodic and myorelaxant effects on isolated strips of duodenum of ex vivo rats. Besides central or peripheral sympathetic nervous system activation, sildenafil possibly acts at the gastrointestinal myocite level by activating the NO/GMPc system. / Estudamos o efeito do citrato de sildenafil (ViagraÂ), vasodilatador largamente utilizado na terapÃutica da disfunÃÃo erÃtil, sobre o comportamento motor do trato gastrintestinal (TGI) de ratos Wistar. Para tanto, utilizamos 175 animais machos, pesando entre 200 a 350g, distribuÃdos nos quatro seguintes grupos de estudo: efeitos do citrato de sildenafil sobre o i) esvaziamento gÃstrico (EG) e os trÃnsitos gastrintestinal (GI) e ii) intestinal de lÃquido em ratos acordados; iii) a complacÃncia gÃstrica de ratos anestesiados e iv) a contratilidade de tiras isoladas do duodeno de ratos ex vivo. i) Avaliamos, em 64 ratos acordados sob jejum e livre acesso à Ãgua por 24h, o efeito da injeÃÃo (0,2mL; e.v.) de sildenafil (4mg/Kg) ou veÃculo (HCl 0,01N) sobre o EG e o trÃnsito GI de lÃquido, bem como sobre a pressÃo arterial (PA). Mediante gavagem, 1,5mL da refeiÃÃo-teste (vermelho de fenol - 0,5mg/mL em glicose a 5%) foi injetada no estÃmago. Depois de 10, 20 ou 30min, sacrificamos os animais e, apÃs laparotomia, obstruÃmos o piloro, o cÃrdia e o Ãleo terminal. Removemos e dividimos o TGI em: estÃmago e segmentos consecutivos do intestino delgado (40% iniciais; 30% mediais e 30% terminais). ApÃs o processamento destas porÃÃes viscerais, determinamos as absorbÃncias das amostras a 560nm. A retenÃÃo fracional de vermelho fenol em cada segmento permitiu o cÃlculo do EG e trÃnsito GI. Em um grupo separado de animais, a PA foi monitorada continuamente por meio de um sistema digital de aquisiÃÃo de dados durante 20min antes e 30min apÃs o tratamento com sildenafil ou diluente. Comparado ao grupo controle, houve aumento significativo da retenÃÃo gÃstrica (44,2Â2,0 vs 53,2Â2,1; 25,4Â1,3 vs 37,3Â1,6; 20,9Â2,5 vs 32,5Â2,9%) nos animais tratados com sildenafil e sacrificados aos 10, 20, ou 30min, respectivamente, bem como retarde significativo no trÃnsito GI. Embora o sildenafil tenha provocado hipotensÃo, a PA retoma nÃveis basais logo apÃs 10min. O prÃ-tratamento com omeprazol (bloqueador da secreÃÃo Ãcida estomacal) nÃo modificou o efeito do sildenafil sobre os valores de retenÃÃo gÃstrica e intestinal nem nos nÃveis de PA. ii) Noutros animais (n=44), sob jejum de 24h e dotados previamente (3d) de uma cÃnula crÃnica no bulbo duodenal, estudamos o efeito do sildenafil sobre a progressÃo ao longo do intestino delgado de uma refeiÃÃo teste (10MBq de TecnÃcio ligado a fitato e diluÃdo em 1mL de salina 0,9%). Decorridos 20, 30 ou 40min da injeÃÃo (0,2mL e.v.) de sildenafil (4mg/Kg) ou diluente (HCL 0,01N), sacrificamos os animais e, apÃs laparotomia e remoÃÃo do TGI, dividimo-o em: estÃmago, cinco segmentos congruentes e consecutivos de intestino delgado e o intestino grosso. A contagem da radiatividade foi determinada num colimador de gama-cÃmara. O sildenafil promoveu retarde (p<0,05) do TI, indicado pelos retardes dos centros geomÃtricos da refeiÃÃo de 2,8 0,2 vs 3,3 0,1; 3,0 0,2 vs 3,7 0,1 e 3,4 0,1 vs 4,2 0,2 em relaÃÃo ao grupo controle, aos 20, 30 ou 40min. iii) Os estudos de complacÃncia gÃstrica foram conduzidos em 39 ratos anestesiados, sob jejum de 24h. As variaÃÃes do volume gÃstrico (VG), foram medidas por pletismografia, enquanto a PA foi monitorada continuamente por um sistema digital de aquisiÃÃo de dados. Em relaÃÃo aos valores basais (2,91Â0,19mL) o sildenafil (3mg/Kg â e.v.) aumentou (p<0,05) o VG apÃs 10, 20 e 30min (3,08Â0,18; 3,10Â0,17 e 3,09Â0,17mL). A PA basal (105,8Â2,28mmHg) caiu significativamente com o sildenafil (59,8Â3,2; 64,8Â3,7 e 59,3Â4,6mmHg) enquanto o diluente (HCl 0,01N) nÃo modificou seja o VG ou a PA. O prÃ-tratamento mediante esplancnotomia ou injeÃÃo e.v. com azul de metileno (3mg/Kg-bloqueador da guanilato ciclase), L-NNA (3mg/Kg-bloqueador da NO sintetase) ou propranolol (2mg/Kg-Ã-bloqueador) preveniram o aumento do VG pelo sildenafil; jà o pÃs-tratamento com nitroprussiato de sÃdio (1mg/Kg - e.v.) o ampliou significativamente. iv) Avaliamos ainda o efeito do sildenafil sobre a contratilidade de tiras isoladas do duodeno de ratos ex vivo (n=28), sacrificados por deslocamento cervical. Tiras dissecadas do duodeno foram suspensas longitudinalmente em cuba de vidro (10mL), plena de soluÃÃo de Tyrode (37oC e pH 7,4), e submetidas a uma tensÃo inicial de 1g. ApÃs 1h de estabilizaÃÃo, a contratilidade espontÃnea ou induzida das tiras foi registrada continuamente por um sistema digital de aquisiÃÃo de dados. O sildenafil em doses crescentes e cumulativas (0,1 a 300Âmol/L) relaxou (EC50 de 9,6Âmol/L) o duodeno, mais atà que o zaprinaste ou a papaverina (bloqueadores de FDEs) (EC50 91,6 e 78,5Âmol/L, nesta ordem). Observamos ademais que o sildenafil inibiu as contraÃÃes induzidas por acetilcolina ou carbacol (IC50 26,7 e 16,2Âmol/L, respectivamente). Jà o prÃ-tratamento com azul de metileno, ODQ (bloqueador da guanilato ciclase) ou L-NAME (bloquedor da NO sintetase), mas nÃo o D-NAME (isÃmero inativo da NO sintetase) preveniram o efeito do sildenafil. O efeito mio-relaxante do sildenafil foi ampliado pela L-arginina (substrato do NO sintetase) ou nitroprussiato de sÃdio (doador de NO). O prÃ-tratamento com forskolina (estimulador da adenilato ciclase) tambÃm aumentou o efeito mio-relaxante do sildenafil. Em resumo, observamos que o sildenafil diminui a motilidade gastrintestinal, retardando o EG, os trÃnsitos GI e intestinal de lÃquido em ratos acordados; aumenta a complacÃncia gÃstrica em ratos anestesiados alÃm de apresentar efeitos antiespasmÃdico e mio-relaxante sobre tiras isoladas de duodeno de ratos ex vivo; por estimulaÃÃo do sistema nervoso simpÃtico e tendo como provÃvel mecanismo de aÃÃo ao nÃvel do miÃcito gastrintestinal a via do NO/GMP cÃclico.