Aquesta tesi presenta els estudis realitzat per avaluar el paper de diferents neurotransmisors i neuromoduladors en respostes de tipus emocional, en el control dels efectes reforçants i gratificants de diverses drogues d'abús així com en la modulació de diferents respostes antinociceptives. En concret, vam avaluar el paper del sistema endocannabinoid, opioid i PACAP en aquestes respostes mitjançant l'ús de diferents soques de ratolins modificatsgenèticament (ratolins knockout). Vàrem estudiar el paper del receptor cannabinoid CB1 en respostes de tipus emocional (ansietat i depressió), així com en els efectes reforçants dels opioids i cocaïna, mitjançant l'ús del ratolí CB1 knockout. Per una altra banda, vam investigar el sistema PACAP en la plasticitat sináptica, en el control de respostes emocionals (ansietat) i sobre els efectes farmacològics dels opioids mitjançant l'ús del ratolí PACAP R-type I knockout. Finalment, el paper dels receptors opioids mu, delta i kappa en el control de diferents tipus de respostes antinociceptives va ser avaluat mitjançat l'ús de ratolins knockout per un, dos o tots tres receptors opioids. / The aim of this thesis was to evaluate the involvement of different neuromodulator and neurotransmitter systems in mediating emotional responses, in the control of the rewarding and reinforcing effects of different drugs of abuse as well as in the modulation of several antinociceptive responses. Specifically we studied the role of the endocannabinoid, opioid and PACAP systems in controlling those responses. For this porpoise, different genetically modified mice lines (knockout mice) were used.We evaluated the role of the CB1 cannabinoid receptor in emotional responses anxiety and depression), as well as in mediating the rewarding and reinforcing effects of opioids and psychostimulants by using the CB1 knockout mice.On the other hand, we investigated the involvement of the PACAP system in synaptic plasticity, in controlling emotional behaviour, and in the modulation of some pharmacological effects produced by opioids by using the PACAP R-type I knockout mice. Finally, the specific role of mu, delta and kappa opioid receptor in analgesia was evaluated by using single, double and triple knockout mice for those receptors.

No description available.

Sono stati studiati gli effetti tossici dell’esposizione cronica a cobalto e cromo. In passato, questa tossicità, che colpiva lavoratori esposti per ragioni occupazionali, è stata un problema molto sentito. Tuttavia, recenti pubblicazioni hanno descritto una specifica tossicità mediata da elevati livelli di cobalto e cromo, anche in pazienti portatori di protesi metalliche, quali gli impianti d’anca. Anche se sintomi clinici tra cui, cecità, sordità e neuropatia periferica, suggeriscono uno specifico neurotropismo, ancora poco è conosciuto delle basi neuropatologiche di questo processo ed oltretutto non ne è ancora stata apportata un’evidenza sperimentale. In questo progetto di ricerca, quindi, si è voluto approfondire il meccanismo patogenetico da cui scaturiscono tali sintomi neurologici, utilizzando come modello sperimentale il coniglio. Conigli New Zealand White sono stati trattati con dosi endovenose ripetute di cobalto e cromo, inoculati singolarmente od in associazione tra loro. Nessuna evidente alterazione clinica o patologica è stata associata alla somministrazione di solo cromo, nonostante gli elevati livelli in sangue e tessuti, mentre i trattati con cobalto-cromo o solo cobalto hanno mostrato segni clinici gravanti sul sistema vestibolo-cocleare; il cobalto, quindi, è stato identificato come il maggiore elemento scatenante neurotossicità. Inoltre all’esame istopatologico gli animali hanno mostrato severa deplezione delle cellule gangliari retiniche e cocleari, assieme a danno al nervo ottico e perdita di cellule sensitive capellute dell’orecchio. È risultato infine evidente che la gravità delle alterazioni è stata correlata al dosaggio ed al tempo di esposizione; dati questi che confermano, quindi, le precedenti osservazioni fatte su pazienti umani esposti a rilascio abnorme di cobalto e cromo da usura di protesi d’anca. È stato ipotizzato che il cobalto agisca sui mitocondri provocando l’incremento di produzione di specie reattive dell’ossigeno e il rilascio di fattori proapoptotici, causando sulle cellule neuronali un danno proporzionale al loro fabbisogno energetico e grado di mielinizzazione. / The toxic effects of continuous exposure to cobalt and chromium have been studied. In the past, this toxicity concerning workers exposed in occupational setting, was a very sensitive issue. However, recent reports have described a specific toxicity mediated by high levels of cobalt and chromium even in patients who had received metallic prostheses, such as hip implants. Although clinical symptoms, including blindness, deafness and peripheral neuropathy, suggest a specific neurotropism, little is still known about the neuropathological basis of this process, and moreover, it has not yet been provided an experimental evidence. So, in this research project we wanted to investigate the pathogenic mechanism from which these neurologic symptoms come out, using rabbit as an experimental model. New Zealand White rabbits were treated with repeated intravenous doses of cobalt and chromium, administered alone or in combination between them. No evident clinical or pathological alteration has been associated with the only chromium administration, despite its high levels in blood and tissue while the cobalt-chromium and cobalt alone treated rabbits showed vestibulo-cochlear signs; cobalt, then, has been identified as the major trigger element mediating neurotoxicity. In addition, on histopathological examination, the animals showed severe depletion of retinal and cochlear ganglion cell along with optic nerve damage and loss of sensory cochlear hair cells. Finally, it has also been clear that the severity of the alterations has been related to the dose and the exposure time. These data confirm previous observations in human patients exposed to abnormal release of cobalt and chromium, arising from damaged hip prostheses. It has been supposed that the cobalt acts on mitochondria leading to increased production of reactive oxygen species and release of pro-apoptotic factors, producing a damage on neuronal cells in proportion to their energy requirements and degree of myelination.

Il presente studio rappresenta la prima applicazione della tecnica CEUS in alcune delle più diffuse specie non convenzionali, nonché la prima nei rettili. In particolare è stata investigata la perfusione di fegato e milza in 10 conigli, 10 furetti e il fegato in 8 iguane. Per quanto riguarda i mammiferi, la tecnica è risultata di facile attuazione e i risultati ottenuti erano equiparabili a quelli documentati per i piccoli animali. Maggiore variabilità si è messa in evidenza a livello splenico in entrambe le specie e nel coniglio rispetto al furetto. Nelle iguane è stata necessaria una modifica del protocollo a seguito dei tempi più lunghi delle fasi di wash in e di wash out. Le curve ottenute erano caratterizzate da picchi più bassi e TTP più lunghi, con wash out incompleto anche dopo 10 minuti di indagine. Nelle iguane l’indagine del fegato è stata approfondita grazie all’esecuzione di TC dinamiche con MDC, studio pioneristico per quanto riguarda la medicina dei rettili. L’esecuzione è avvenuta senza problemi in anestesia generale. Diffusione del MDC e conseguenti variazione di HU a livello aortico e epatico sono state considerate contemporaneamente, con costruzione di curve HU-tempo piuttosto ripetibili, entrambe caratterizzate da un wash in rapido, un picco, particolarmente alto a livello aortico, e da una fase di wash out più lento, anche qui incompleto dopo i 600 secondi di indagine. Una certa variabilità è stata notata in tre individui, risultato attendibile conseguentemente alla forte dipendenza da fattori intriseci ed estrinseci del metabolismo e della funzionalità epatica dei rettili. L’intero protocollo è stato applicato in un furetto e due iguane patologiche, al fine di evidenziare le potenzialità cliniche delle tecniche. Sebbene il numero esiguo di casi non permetta di trarre conclusioni a questo riguardo, l’ultimo capitolo della tesi vuole essere uno spunto per studi futuri. / The present work represents the first application of CEUS in some of the most overspread exotic pets and in reptiles in general. We investigated liver and spleen perfusion in 10 rabbits, and 10 ferrets other than the liver perfusion in 8 green iguanas. The technique was easily performed in the mammals, and results were similar to the one already reported for small mammals. More variability was highlighted for the spleen in both species and for the rabbit compared to the ferret. Small modifications were necessary to adapt the protocol to the longer phases occurring in the iguana. Curves obtained for this species were characterized by smaller peaks and longer TTP, and wash out phase was not complete over the 600 seconds of the study. Liver perfusion was further investigated in the iguana by a dynamic contrast enhanced CT scan, a pioneer study in reptile medicine. The technique was easily performed under general anesthesia. MDC diffusion was evaluated by HU variations both in the aorta and in the hepatic vessels and parenchyma at the same time, and time-intensity curves were determined. The shape of the curves was repeated in all the animals in a very similar way, even if few variation were noticed, probably as a consequence of the strong dependence of reptile metabolism and liver function both to intrisic and extrinsic factors. The whole protocol was applied in two pathological iguanas and one pathological ferret, in order to investigate clinical potentiality of the techniques. Even if no conclusion can be derived, the final section of the thesis should represent a cue for future studies.

Water is susceptible to be used for numerous purposes, including edible, both for humans and animals. In the food animal production, drinking water is frequently used as a way to carry out the most common pharmacological treatments. In these cases, there are many variables which could degrade drugs dissolved in this mean, even when properly arranged pharmaceutical formulations are used. In fact, although a product obtains a Marketing Authorization through appropriate laboratory studies both drug stability and solubility, on the other hand the solubility of the same drug in natural water used as a drinking water is not documented. In the present study has been evaluated the dissolution kinetics (at 0 hours and 24 hours) of products, having oxytetracycline and tylosin as active ingredient, used in drinking water samples in order to see how the different physical and chemical factors that characterize the drinking water may affect therapeutic efficacy. In fact, multiple factors, also of little relevance if individually considered, are able to adversely affect the pharmacological treatment carried out in drinking water.

The detection of endogenous anabolic androgenic steroids (EAAS) is one of the most difficult analytical challenges in the doping control field. The main problem for their detection is to distinguish between normally endogenous concentrations and those observed after the exogenous administration of an EAAS. The screening methods for EAAS are currently based on the determination of the steroid profile and the application of the athlete biological passport. The inclusion of new steroid metabolites can improve the screening capabilities of the steroid profile. Thus, the objective of the thesis is to elucidate and characterize new testosterone metabolites that can be implemented to the current steroid profile and to evaluate their usefulness for doping control analysis. Four unreported testosterone metabolites were detected and characterized by using liquid chromatography coupled to tandem mass spectrometry approaches. These compounds were demonstrated to come from degradation of cysteine conjugates. The formation of these conjugates implies an addition of a double bond as a phase I metabolism followed by conjugation with glutathione and the subsequent transformation to cysteine conjugates in urine. In order to determinate the usefulness of the cysteinyl compounds for doping control purposes, a quantitative method for the indirect determination of these compounds was developed and validated. Using this method, reference population limits were established by the analysis of 174 urine samples. Additionally, different factors that can potentially influence the excretion of these compounds were evaluated. Finally, the usefulness of these cysteinyl metabolites for the detection of EAAS misuse was evaluated by the analysis of samples collected after different EAAS administration. The use of these metabolites seems to improve in some cases the detection capabilities of the current marker used in routine analysis. / La detecció d’esteroides androgènics anabolitzants endògens (EAAE) és un dels reptes analítics més difícils en la lluita contra el dopatge. El problema més important per a la seva detecció és distingir entre concentracions endògenes i aquelles que s’observen després de l’administració exògena d’un EAAE. Els mètodes de cribatge per a la detecció d’EAAE estan basats en la determinació del perfil esteroïdal i la introducció d’aquest en el passaport biològic de l’atleta. La inclusió de nous metabòlits d’esteroides pot ajudar a millorar les capacitats de cribatge del perfil esteroïdal. Per tant, l’objectiu d’aquesta tesis és detectar i caracteritzar nous metabòlits d’EAAE que puguin implementar-se en l’actual perfil esteroïdal i l’avaluació de la seva utilitat en la lluita contra el dopatge. Quatre metabòlits desconeguts de la testosterona van ser detectats i caracteritzats mitjançant la utilització de la cromatografia líquida acoblada a l’espectrometria de masses en tàndem. L’origen d’aquests compostos es va demostrar que provenia de la degradació de conjugats amb cisteïna. La formació d’aquests conjugats implica l’addició d’un doble enllaç com a reacció metabòlica de fase I acompanyat per la conjugació amb glutationa i la subseqüent degradació d’aquesta a cisteïna en orina. Per tal de poder veure la seva aplicació en el camp del dopatge, es va desenvolupar i validar un mètode per la quantificació indirecta d’aquests compostos en orina. Utilitzant aquest mètode es van establir límits de referència basats en l’anàlisi de 174 mostres de orina. Addicionalment, diferents factors descrits que poden afectar l’excreció en orina d’aquests compostos també van ser estudiats en detall. Finalment, es va avaluar la utilitat d’aquests metabòlits conjugats amb cisteïna per a la detecció de l’abús d’EAAE mitjançant l’ anàlisis de mostres després de l’administració de diferents EAAE. L’ús d’aquests metabòlits va millorar (en alguns casos) els temps de detecció comparant-los amb els actuals marcadors utilitzats en rutina.

La caracterització de diversos fàrmacs capaços d’unir-se a receptors associats a proteïnes G (GPCR)s ha revelat que els seus mecanismes d’acció no eren tan simples com es creia. Primer, l’anàlisi de la seva afinitat d’unió per una sèrie de receptors va revelar que podien unir-se a múltiples dianes. Més tard, l’estudi de la seva eficàcia envers diferents vies de senyalització va revelar que alguns fàrmacs podien promoure selectivitat funcional. En aquesta tesi, s’han construït models a partir de noves dades estructurals i farmacològiques de diversos receptors per determinar les bases de l’afinitat de diferents compostos per múltiples GPCRs i estudiar la seva selectivitat funcional. La informació obtinguda pot permetre obtenir noves eines moleculars que ajudin a analitzar la rellevància de diversos modes d’activació en el tractament de malalties complexes com l’esquizofrènia. Aquesta informació també pot contribuir al disseny racional de nous fàrmacs capaços d’explotar diferents perfils de selectivitat i de discriminar entre efectes terapèutics i secundaris. / Deeper characterization of drugs targeting G protein-coupled receptors (GPCR)s has shown that their mechanisms of action can be more complex than previously thought. On the one hand, binding affinity analyses towards a panel of related receptors have revealed that most drugs have affinity for multiple targets. On the other, characterization of drug efficacy for different receptor pathways has made evident that some ligands can selectively activate particular pathways, thus acting as biased agonists. In this work, we used models derived from new experimental data on receptor 3D structure and pharmacology to rationalize the structural determinants of multi-target affinity and biased agonism for different GPCR ligands. This insight can help obtain new molecular probes to assess the importance of specific affinity and efficacy profiles for the treatment of complex diseases such as schizophrenia. Furthermore, it can set the basis for the rational design of new ligands exploiting different forms of selectivity and capable of separating therapeutic effects from side effects.

La contaminazione chimica rappresenta uno dei rischi principali per la sicurezza alimentare e può arrecare anche gravi danni alla salute umana. Rientrano in questa tesi di dottorato tre famiglie di contaminanti: Micotossine, Metalli e Insetticidi. La ricerca di aflatossina B1 è stata effettuata su 90 confezioni di farina, sia biologici sia convenzionali. La presenza della micotossina è stata rilevata solo nelle farine di mais. Solo un campione di produzione convenzionale ha superato il limite di 2 ppb definito per legge. Il dato di maggior rilievo è stato che il quantitativo di 5 grammi di campionamento si è dimostrato non rappresentativo sul totale della confezione commerciale di farina. Più attendibile si è invece dimostrato un campionamento di 20 grammi. L’aflatossina M1 è stata ricercata in 58 campioni di latte di cui 35 sono risultati positivi. Tuttavia, i livelli riscontrati erano costantemente inferiori al limite previsto per legge. Sono stati sottoposti a estrazione e purificazione, e analizzati con metodica HPLC-FL per la ricerca di Ocratossina A, 114 campioni di bile, 35 campioni di plasma, 40 campioni di rene prelevati da polli in Giordania. Le analisi hanno fornito risultati costantemente negativi. Sono stati analizzati 72 campioni (30 di muscolo, 29 di fegato e 13 di rene) prelevati da 30 bovini nel macello di Irbid (Giordania), di età compresa tra 8 e 30 mesi e provenienti da allevamenti diversi, per la ricerca di 13 elementi essenziali e non essenziali. In questo studio nessun campione supera i livelli massimi stabiliti dalla normativa europea per quanto riguarda gli elementi considerati. Infine, sono stati analizzati 37 campioni di latte ovino e 31 campioni di latte bovino, prelevati in Giordania in diversi allevamenti, per la ricerca di 4 neonicotinoidi (imidacloprid, acetamiprid, thiamethoxam e thiacloprid). I campioni, analizzati con sistema HPLC/MS/MS, sono risultati costantemente negativi ai quattro neonicotinoidi ricercati. / The safety of animal origin products and human food are crucial for consumers. One of the main risks for food security is represented by the chemical contamination of food, which can cause serious harm to human health . Three chemical contaminants were studied: Mycotoxins, Metals and Pesticides. The experimental test for aflatoxin B1 was conducted on 90 organic and conventional flour. This study shows that only corn flour samples were positive for AFB1 and only one sample exceeded the limit of 2 ppb defined by law. This study shows that a quantity of 5 grams of flour sample is not representative for a 1 kg flour commercial package. We find that 20 grams are more reliable. The experimental test for aflatoxin M1 was conducted on 58 milk samples, and 35 were positive for AFM1. The concentration of AFM1 in these samples never exceeded the level required by law. Different tissue samples were collected from chickens in Jordan including 114 samples of bile, 35 plasma samples and 40 samples of kidney. All samples were subjected to extraction and purification, and subsequently analyzed by HPLC-FL, for Ochratoxin A. The analysis gave consistently negative results. We analyzed 72 samples (30 muscle, 29 liver and 13 kidney) taken from 30 cattle in the slaughterhouse of Irbid (Jordan) and from different farms, aged between 8 and 30 months, for the detection of 13 essential and non-essential elements. In this study, no sample exceeded the maximum levels set by European legislation. Finally, we analyzed 37 samples of sheep milk and 31 of cow milk, taken from different farms in Jordan, to search for the neonicotinoids: imidacloprid, acetamiprid, thiacloprid and thiamethoxam. The samples were analyzed by HPLC/MS/MS. In all samples the neonicotinoids were no detectable.

Metabolic studies of doping agents have been traditionally performed by using gas chromatography coupled to mass spectrometry (GC-MS). In the last years, liquid chromatography coupled to mass spectrometry (LC-MS) has demonstrated to offer new possibilities to perform metabolic studies. The objective of this thesis was to study the metabolism (phase I and phase II) of different doping agents by LC-MS/MS in order to improve the detection capabilities of the studied substances. For mesocarb, a thermolabile compound, the parent drug 19 metabolites were detected in urine including mono-, di- and tri-hydroxylated metabolites excreted free or conjugated with glucuronic acid and sulphate. For toremifene, an anti-estrogenic drug with poor electron ionization properties, the parent drug and 20 metabolites were detected in urine. The structure of most of the metabolites was proposed. Anabolic androgenic steroids (AAS) metabolites conjugated with sulphate were investigated to improve the retrospectivity of the detection of these compounds. A study of hydrolysis and MS/MS behaviour of sulphate metabolites of AAS was performed, and sulphate conjugated metabolites of boldenone, methyltestosterone and metandienone were studied. Boldenone sulphate and epiboldenone sulphate were identified as boldenone metabolites in humans. They can be used as markers of exogenous boldenone administration. For methyltestosterone, three new sulphate metabolites were detected and structures were proposed. One of them, 17β-methyl-5α-androstan-3α,17α-diol 3α-sulphate was detected in urine up to 21 days after methyltestosterone administration, improving three times the retrospectivity of the detection with respect to other previously reported long-term metabolites. Several new sulphate metabolites were detected after metandienone administration. One of them was characterized as 18-nor-17β-hydroxymethyl-17α-methylandrost-1,4,13-triene-3-one conjugated with sulphate, and it was detected up to 26 days after administration, improving the retrospectivity of the detection with respect to other long-term metabolites described. The usefulness of LC-MS/MS for the detection and characterization of metabolites of doping agents has been demonstrated, especially for the study of new phase II metabolites and for metabolic studies of compounds where GC-MS shows relevant limitations. / Els estudis metabòlics de substàncies dopants han estat tradicionalment realitzats mitjançant l’ús de cromatografia de gasos acoblada a espectrometria de masses (GC-MS). En els últims anys, s’ha demostrat la utilitat de la cromatografia líquida acoblada a espectrometria de masses (LC-MS) per realitzar estudis de metabolisme. L’objectiu d’aquesta tesi va ser estudiar el metabolisme (fase I i fase II) de diferents substàncies dopants mitjançant LC-MS/MS per tal de millorar la capacitat de detecció dels compostos estudiats. Per a mesocarb, compost termolàbil, es van detectar en orina el compost inalterat i 19 metabòlits incloent metabòlits mono-, di- i tri-hidroxilats excretats lliures o conjugats amb àcid glucurònic i sulfat. Per a toremifè, un fàrmac anti-estrogènic amb espectre de masses d’impacte electrònic amb pocs ions diganòstic, es van detectar el compost inalterat i 20 metabòlits en orina. Es va proposar l’estructura de la major part de metabòlits detectats. Per tal de millorar la retrospectivitat de la detecció dels esteroides anabolitzants androgènics (AAS) es van estudiar els metabòlits conjugats amb sulfat. Es va realitzar un estudi de la hidròlisi i del comportament espectromètric dels metabòlits conjugats amb sulfat dels AAS. Es van estudiar els metabòlits conjugats amb sulfat de boldenona, metiltestosterona i metandienona. Es van identificar boldenona sulfat i epiboldenona sulfat com a metabòlits de boldenona en humans. Aquests metabòlits poden ser usats com a marcadors de l’administració exògena de boldenona. Per a metiltestosterona, es van detectar i proposar les estructures de tres nous metabòlits conjugats amb sulfat. Un d’ells, el 17β-metil-5α-androstà-3α,17α-diol 3α-sulfat, va ser detectat en orina fins a 21 dies després de l’administració de metiltestosterona. Es van detectar diversos metabòlits de metandienona conjugats amb sulfat no descrits prèviament. Un d’ells, identificat com a 18-nor-17β-hidroximetil-17α-metilandrost-1,4,13-trien-3-ona conjugat amb sulfat, va ser detectat fins 26 dies després de l’administració. Tant per a metiltestosterone com per a metandienone, els metabòlits conjugats amb sulfat permeten millorar la retrospectivitat de la detecció respecte a altres marcadors descrits anteriorment. S’ha demostrat la utilitat del LC-MS/MS per a la detecció i caracterització de metabòlits de substàncies dopants, especialment per a l’estudi de nous metabòlits de fase II i per a estudis de metabolisme de compostos que mostren limitacions en GC-MS.

In medicinal chemistry, two chemical fragments are considered bioisosteric if they bind to the same protein environment. Accordingly, looking at the same players from an opposite perspective, two protein environments can be considered chemoisosteric if they interact with the same chemical fragment. In this respect, this Thesis introduces the term chemoisosterism, which represents a new concept in drug discovery. Currently available crystal structures for protein-ligand complexes constitute a basis for the identification of chemoisosteric protein environments, of great utility for the construction of focused fragment chemical libraries. Under the premise that similar protein environments will probably bind to similar fragments, a novel approach to assess protein environment similarities is introduced and used to predict new chemoisosteric relationships. Examples of the potential applicability of chemoisosterism in fragment-based drug discovery are provided. The implications of chemoisosterism for drug polypharmacology are explored, leading to the speculation that the levels of polypharmacology observed in current drugs may just be a latent signature of the exploitation of chemoisosterism during evolution. / En química mèdica, dos fragments moleculars són considerats bioisostèrics si s’uneixen al mateix entorn de proteïna. Canviant la perspectiva sobre el mateix esdeveniment, dos entorns de proteïna poden ésser considerats quimioisostèrics si interaccionen amb el mateix fragment molecular. Aquesta Tesi introdueix el terme quimioisosterisme, un nou concepte en química farmacèutica. Les estructures actualment disponibles de complexos de proteïna i lligand constitueixen una font d’entorns de proteïna quimioisostèrics potencialment útils per a la construcció de llibreries de fragments moleculars dirigides a una proteïna diana en particular. Partint de la premissa que entorns de proteïna similars molt probablement interaccionaran amb fragments moleculars similars, aquesta Tesi presenta un nou mètode per a identificar entorns de proteïna similars, utilitzat per predir noves relacions quimioisostèriques. S’aporten també alguns exemples de potencials aplicacions del quimioisosterisme en la disciplina del descobriment de fàrmacs. Un anàlisis de les implicacions que té el quimioisosterisme en la polifarmacologia ens duu a la hipòtesis de que els nivells de polifarmacologia observats en la majoria de fàrmacs no són res més que una signatura de l’explotació del quimioisosterisme al llarg de l’evolució.