Made available in DSpace on 2016-04-28T20:18:31Z (GMT). No. of bitstreams: 1 2008 - Cristiane Belchior Caloiero.pdf: 424554 bytes, checksum: 418546c1b267e0fbd474d742aa991711 (MD5) Previous issue date: 2008-05-08 / The ovariohysterectomy (OHE) is the most common surgery realized in the small animals hospitals in order to control animal population and to prevent future problems of reproductive order. This surgical procedure has a moderate degree of pain and requires analgesic treatment. Postoperative pain, when not correctly diagnosed and treated, instead of being a mechanism of natural defense, becomes harmful and promote systemic alterations that delays the recovery of the patient. The objective of this study was to compare the analgesic effect in the trans and postoperative period between morphine, tramadol and buprenorphine, that were given to cats prior having OHE. In this study, 30 cats were used, with no specific breed and healthy. The animals were distributed in three groups of 10 animals. Group M received daily pre-anesthesic medication (PAM), acepromazine maleate (0.05 mg/kg) and morphine sulfate (0.2 mg/kg) intramuscularly (IM). Group T received acepromazine (0.05 mg/kg) and Tramadol (2.0 mg/kg) IM and Group B received acepromazine in the same dose and buprenorphine (0.01 mg/Kg) IM. After 20 min of applying PAM, the animals received an induction of the anesthesic thiopental 2.5% in the dose of 12.5 mg/kg intravenously. The animals were kept with isoflurane diluted in 100% oxygen through the universal vaporizer, connected to a circuit of Mapleson D (Baraka). The evaluation of pain and sedation was done by one person who observed for all the animals, and he did not know the treatment used (double blind). The evaluation times were: daily presurgical; 10 min, 20 min and 30 min of surgery and 1, 2, 4 and 6 hours after surgery. The subjective evaluation of pain was done through a visual analogue scales (VAS) and through a descriptive scale before and after the surgery. The measurements of cardiac frequency (FC), respiratory frequency (FR), temperature (Temp), plasma glucose (GL), time of capillary perfusion (TPC) and analysis of mucosa were made moments before, during, and after the surgery. The gauging of the systolic arterial pressure (PAS) and saturation of oxygen hemoglobin (SpO2) were made only during the surgical procedure. The comparison of the objective and subjective parameters between the three groups was done by using the Analysis of Variance of Kruskal-Wallis, followed of the Mann-Whitney test, whenever were significant differences between the treatments (p< 0.05). Inside of each group, the Analysis of Variance of Friedman was used for the comparisons between the diverse moments, followed by the test of Wilcoxon for the identification of the different moments (p< 0.05). Animals of the buprenorfina group (B) were more sedate in all the evaluated moments, followed by the group morphine (M) and finally the group tramadol (T). In the evaluation of pain for the VAS, the group tramadol demonstrated a lesser degree of pain in the first the 2 hours, followed by the groups with morphine and buprenorphine. In the evaluation of pain for the descriptive scale, tramadol presented better analgesic effect at the times 2, 4, and 6 hours. The values of cardiac frequency remained relatively constant during the surgical procedure, only being different at the times 4 and 6 hours where the buprenorphine group presented higher values. In the present study, the reduction of the FR was more accentuated in the morphine group. Difference in the PAS between the groups was not observed. The buprenorphine group presented higher values of glucose at the moment 6 hours. In this study, the body temperature did not differ between the groups in the pre or postoperative moments. With this study, it can be concluded that tramadol, in the given dose and regimen, is more efficient than the morphine and buprenorphine in controlling of postoperative pain of OHE in cats, without signs of collateral effect. / A ovariossalpingo-histerectomia (OSH) ? a cirurgia mais comumente realizada na cl?nica de pequenos animais com objetivos de controlar a popula??o e evitar problemas futuros de ordem reprodutiva. Este procedimento cir?rgico cursa num grau de dor moderado requisitando de um tratamento analg?sico adequado. A dor p?s-operat?ria, quando n?o corretamente diagnosticada e tratada, deixa de ser um mecanismo de defesa natural e torna-se nociva, promovendo altera??es sist?micas relevantes que retardam a recupera??o do paciente. O objetivo deste trabalho foi comparar o efeito analg?sico no per?odo trans e p?s-operat?rio entre morfina, tramadol e buprenorfina administrados preventivamente em gatas submetidas a OSH. Neste estudo foram utilizadas 30 gatas, sem ra?a definida e h?gidas. Os animais foram distribu?dos aleatoriamente em tr?s grupos de 10 animais. O grupo M recebeu de medica??o pr?-anest?sica (MPA), maleato de acepromazina (0,05 mg/kg) e sulfato de morfina (0,2 mg/kg) pela via intramuscular (IM). O grupo T recebeu acepromazina (0,05 mg/kg) e Tramadol (2 mg/kg) pela via IM. Ao grupo B foi administrado acepromazina na mesma dose e buprenorfina (0,01 mg/Kg) via IM. Ap?s 20 min da MPA, os animais recebiam de indu??o anest?sica tiopental 2,5% na dose de 12,5 mg/kg pela via intravenosa. Os animais eram intubados e mantidos com isoflurano dilu?do em oxig?nio a 100% atrav?s do vaporizador universal, conectados a um circuito de Mapleson D (Baraka). A avalia??o da dor e seda??o foi realizada por um mesmo observador em todos os animais, e este n?o conhecia o tratamento utilizado (duplo cego). Os tempos de avalia??o eram: pr?-operat?rio; 10, 20 e 30 minutos de cirurgia, 1, 2, 4 e 6 horas ap?s o t?rmino da mesma. A avalia??o subjetiva da dor foi realizada atrav?s da escala an?loga visual e da escala descritiva nos momentos antes e ap?s a cirurgia. A mensura??o dos par?metros objetivos freq??ncia card?aca (FC), freq??ncia respirat?ria (FR), temperatura (Temp), glicemia (GL), tempo de perfus?o capilar (TPC) e an?lise de mucosas foram realizados nos momentos antes, durante e ap?s a cirurgia, j? a aferi??o da press?o arterial sist?lica (PAS) e satura??o de oxig?nio na hemoglobina (SpO2) foram realizadas somente durante o procedimento cir?rgico. A compara??o dos par?metros objetivos e subjetivos entre os tr?s grupos foi realizada pela An?lise de Vari?ncia de Kruskal-Wallis, seguido do teste Mann-Whitney, sempre que houvesse diferen?as significativas entre os tratamentos (p< 0,05). Dentro de cada grupo, foi utilizada pela An?lise de Vari?ncia de Friedman para as compara??es entre os diversos momentos, seguido do teste de Wilcoxon para a identifica??o dos momentos diferentes (p< 0,05). Os animais do grupo buprenorfina (B) se apresentaram mais sedados em todos os momentos avaliados, seguido do grupo morfina (M) e por ?ltimo o grupo tramadol (T). Na avalia??o da dor pela VAS, o grupo tramadol demonstrou um menor grau de dor nas primeiras 2 horas, seguido pelos grupos morfina e buprenorfina. Na avalia??o da dor pela escala descritiva, o tramadol apresentou melhor efeito analg?sico nos momentos 2, 4, e 6 horas. Os valores de freq??ncia card?aca permaneceu relativamente constante durante todo o procedimento cir?rgico, s? sendo diferente nos momentos 4 e 6 horas onde a buprenorfina apresentou valores mais altos. No presente estudo, a diminui??o da FR foi mais pronunciada no grupo morfina. N?o foi observada diferen?a na PAS entre os grupos. O grupo buprenorfina apresentou valores mais altos de glicose no momento 6 horas. Neste estudo, a temperatura corporal n?o diferiu entre os grupos nos momentos pr? e p?s-operat?rio. Com este estudo, pode-se concluir que o tramadol na dose e regime empregados mostrou-se mais eficiente que a morfina e a buprenorfina em controlar a dor p?s-operat?ria da OSH em gatas, sem apresentar efeitos colaterais.

The underlying nociceptive mechanisms in temporomandibular joint (TMJ) and masticatory muscles in many pain conditions are still unclear, largely due to the limited study of peripheral and central neural mechanisms affecting craniofacial musculoskeletal tissues. This study provided evidence in support of Hypothesis 1: Peripheral glutamatergic and capsaicin-sensitive mechanisms modulate the properties of primary afferents and brainstem neurons processing deep craniofacial nociceptive information. Effects of glutamate and capsaicin injected into the receptive field of deep craniofacial nociceptive afferents or TMJ of TMJ-responsive nociceptive neurons in trigeminal subnucleus caudalis/upper cervical cord (Vc/UCC) were studied in halothane-anesthetized rats. When injected alone, glutamate and capsaicin activated and induced peripheral sensitization in many afferents. Following glutamate injection, capsaicin-evoked activity was greater than that evoked by capsaicin alone, whereas following capsaicin injection, glutamate-evoked responses were similar to those of glutamate alone. When injected alone, glutamate and capsaicin also activated and induced central sensitization in most Vc/UCC neurons. Following glutamate injection, capsaicin evoked greater activity and less sensitization compared with capsaicin alone, whereas following capsaicin, glutamate was less effective in activating and sensitizing most Vc/UCC neurons. This apparent desensitizing effect of capsaicin on glutamate-evoked excitability of Vc/UCC neurons contrasts with the lack of capsaicin-induced modulation of glutamate-evoked afferent excitability, suggesting that peripheral and central sensitization may be differentially involved in the nociceptive effects of glutamate and capsaicin applied to deep craniofacial tissues. Further evidence of glutamate-capsaicin interactions was documented in the attenuation by TMJ pre-injection of glutamate receptor antagonists of jaw muscle activity reflexly evoked by TMJ injection of capsaicin. Moreover, additional findings support Hypothesis 2: Surgical cutaneous incision modulates the properties of brainstem neurons processing deep craniofacial nociceptive information. TMJ-responsive nociceptive Vc/UCC neurons could be activated by surgical incision of the skin overlying the TMJ and this incision-induced afferent barrage caused nociceptive neurons to be temporarily refractory to further capsaicin-induced central sensitization. These novel findings suggest that peripheral glutamate and capsaicin receptor mechanisms as well as surgical cutaneous incision may be involved in the nociceptive processing of deep craniofacial afferent inputs and may interact to modulate both activation as well as sensitization evoked from these tissues.

The underlying nociceptive mechanisms in temporomandibular joint (TMJ) and masticatory muscles in many pain conditions are still unclear, largely due to the limited study of peripheral and central neural mechanisms affecting craniofacial musculoskeletal tissues. This study provided evidence in support of Hypothesis 1: Peripheral glutamatergic and capsaicin-sensitive mechanisms modulate the properties of primary afferents and brainstem neurons processing deep craniofacial nociceptive information. Effects of glutamate and capsaicin injected into the receptive field of deep craniofacial nociceptive afferents or TMJ of TMJ-responsive nociceptive neurons in trigeminal subnucleus caudalis/upper cervical cord (Vc/UCC) were studied in halothane-anesthetized rats. When injected alone, glutamate and capsaicin activated and induced peripheral sensitization in many afferents. Following glutamate injection, capsaicin-evoked activity was greater than that evoked by capsaicin alone, whereas following capsaicin injection, glutamate-evoked responses were similar to those of glutamate alone. When injected alone, glutamate and capsaicin also activated and induced central sensitization in most Vc/UCC neurons. Following glutamate injection, capsaicin evoked greater activity and less sensitization compared with capsaicin alone, whereas following capsaicin, glutamate was less effective in activating and sensitizing most Vc/UCC neurons. This apparent desensitizing effect of capsaicin on glutamate-evoked excitability of Vc/UCC neurons contrasts with the lack of capsaicin-induced modulation of glutamate-evoked afferent excitability, suggesting that peripheral and central sensitization may be differentially involved in the nociceptive effects of glutamate and capsaicin applied to deep craniofacial tissues. Further evidence of glutamate-capsaicin interactions was documented in the attenuation by TMJ pre-injection of glutamate receptor antagonists of jaw muscle activity reflexly evoked by TMJ injection of capsaicin. Moreover, additional findings support Hypothesis 2: Surgical cutaneous incision modulates the properties of brainstem neurons processing deep craniofacial nociceptive information. TMJ-responsive nociceptive Vc/UCC neurons could be activated by surgical incision of the skin overlying the TMJ and this incision-induced afferent barrage caused nociceptive neurons to be temporarily refractory to further capsaicin-induced central sensitization. These novel findings suggest that peripheral glutamate and capsaicin receptor mechanisms as well as surgical cutaneous incision may be involved in the nociceptive processing of deep craniofacial afferent inputs and may interact to modulate both activation as well as sensitization evoked from these tissues.

Hypersensitivity after tissue injury is an expression of neuronal plasticity in the central nervous system. This has been explored most extensively using in vitro preparations and animal models of inflammatory pain and chemical irritation. For pain after surgery, a similar process has been proposed. In the present study, we examined dorsal horn neuron (DHN) sensitization using the plantar incision model for post-operative pain. In behavioral experiments, the effect of a local anesthetic injection (or saline vehicle) 15min before plantar incision on pain behaviors several days after incision was studied. Bupivacaine injection before incision prevented pain behaviors until 4h afterwards; injection after incision produced the same effect. One day after incision, pain behaviors were not different between rats injected with saline or bupivacaine. In neurophysiologic experiments, however, bupivacaine injection blocked activation of DHNs during incision. One hour after incision, expansion of receptive fields (RFs) to pinch and increased background activity occurred in 14 of 16 neurons in the saline group but only in two of 22 neurons in the bupivacaine group. The difference was not due to a systemic effect of bupivacaine. Ten sensitized neurons were studied using the injection of bupivacaine 90min after incision. Increased background activity (n=7) and expanded RFs (n=7) were reversed by bupivacaine. Sensitization was re-established in seven of eight neurons 2h after injection as the local anesthetic dissipated. These results indicate that activation of DHNs during plantar incision and sensitization 1h later are not necessary for subsequent pain behaviors. Because sensitization was reversed 90min after plantar incision and then re-established as the local anesthetic effect diminished, enhanced responsiveness of DHN requires ongoing afferent input during the first day after incision.