Pathological Gambling (PG) is an impulse control disorder with lifetime prevalence of 1-3%. Available treatments are limited by uncertain classification and complexity of implicated neurotransmitter systems. Dopamine (DA), a key neurotransmitter implicated in addictive behavior and reward is elevated in response to gambling and psychostimulants. Based on previous research, it was hypothesized that the D2 blocker, haloperidol (HAL), will enhance slot machine reinforcement in PG but not in Healthy Controls (HC). If this increase reflects preferential stimulation of D1 receptors and group differences in D1 sensitivity, D1-D2 blocker (fluphenazine, FLU) should offset increase in reinforcement seen with HAL in PG subjects. In line with DA's implicated role in 'wanting' vs. 'liking' of the addictive reinforcer, the results suggest that DA release mediated partial D1 activation under FLU led to clear differentiation between groups with increased 'wanting' seen in controls but not in gamblers. DA's role in 'liking' however remains elusive.

Pathological Gambling (PG) is an impulse control disorder with lifetime prevalence of 1-3%. Available treatments are limited by uncertain classification and complexity of implicated neurotransmitter systems. Dopamine (DA), a key neurotransmitter implicated in addictive behavior and reward is elevated in response to gambling and psychostimulants. Based on previous research, it was hypothesized that the D2 blocker, haloperidol (HAL), will enhance slot machine reinforcement in PG but not in Healthy Controls (HC). If this increase reflects preferential stimulation of D1 receptors and group differences in D1 sensitivity, D1-D2 blocker (fluphenazine, FLU) should offset increase in reinforcement seen with HAL in PG subjects. In line with DA's implicated role in 'wanting' vs. 'liking' of the addictive reinforcer, the results suggest that DA release mediated partial D1 activation under FLU led to clear differentiation between groups with increased 'wanting' seen in controls but not in gamblers. DA's role in 'liking' however remains elusive.

This study used the D2-preferring dopamine antagonist, haloperidol (3mg) and D1-D2 antagonist, fluphenazine (3mg) to investigate the roles of D1 and D2 receptors in d-amphetamine (20-mg) reinforcement in humans with (9 M; 7 F) and without (12 M; 4 F) an addictive disorder, in a placebo-controlled, between-within counterbalanced design. To preclude neurotoxicity, pathological gamblers served to evaluate effects of addiction status. Incentive motivation (e.g., Desire to Gamble), hedonic impact (e.g., Liking) and risky decision-making were assessed. Haloperidol reduced Desire to Gamble in controls, whereas fluphenazine reduced Desire in gamblers. Both antagonists reduced hedonic impact in both groups, with fluphenazine exhibiting stronger effects in gamblers. Both antagonists decreased risky decisions in controls but increased risky decisions in gamblers. Results suggest that D1 mediates amphetamine-induced motivation to gamble; D2 mediates amphetamine’s hedonic effects; D1 function is deficient in gamblers; and D2 blockade may reverse a restorative effect of amphetamine in addicted individuals.

This study used the D2-preferring dopamine antagonist, haloperidol (3mg) and D1-D2 antagonist, fluphenazine (3mg) to investigate the roles of D1 and D2 receptors in d-amphetamine (20-mg) reinforcement in humans with (9 M; 7 F) and without (12 M; 4 F) an addictive disorder, in a placebo-controlled, between-within counterbalanced design. To preclude neurotoxicity, pathological gamblers served to evaluate effects of addiction status. Incentive motivation (e.g., Desire to Gamble), hedonic impact (e.g., Liking) and risky decision-making were assessed. Haloperidol reduced Desire to Gamble in controls, whereas fluphenazine reduced Desire in gamblers. Both antagonists reduced hedonic impact in both groups, with fluphenazine exhibiting stronger effects in gamblers. Both antagonists decreased risky decisions in controls but increased risky decisions in gamblers. Results suggest that D1 mediates amphetamine-induced motivation to gamble; D2 mediates amphetamine’s hedonic effects; D1 function is deficient in gamblers; and D2 blockade may reverse a restorative effect of amphetamine in addicted individuals.

This study sought to determine the roles of D1 and D2 receptors in mediating gambling reinforcement in pathological gamblers and controls (n=24/group), and the influence of reward novelty on these effects. Subjects received D2 antagonist, haloperidol (3mg), or D1-D2 antagonist, fluphenazine (3mg) in a placebo-controlled, counterbalanced, two-session design. Incentive motivation and hedonic impact were assessed before and after a 15-min slot machine game. Haloperidol tended to increase pre-game motivation but reduce the priming effect of the slot machine, while fluphenazine increased positive mood ratings but reduced motivation to gamble. Haloperidol effects were stronger when it was received on the first session, while fluphenazine had stronger effects after prior drug-free exposure. Results suggest D1 signaling is central to reward expectancy and motivation to gamble, and that moderate stimulation increases positive affect while reducing motivation to gamble. D1 blockade may also enhance reinforcement of a familiar task by interfering with reward expectancy.

This study sought to determine the roles of D1 and D2 receptors in mediating gambling reinforcement in pathological gamblers and controls (n=24/group), and the influence of reward novelty on these effects. Subjects received D2 antagonist, haloperidol (3mg), or D1-D2 antagonist, fluphenazine (3mg) in a placebo-controlled, counterbalanced, two-session design. Incentive motivation and hedonic impact were assessed before and after a 15-min slot machine game. Haloperidol tended to increase pre-game motivation but reduce the priming effect of the slot machine, while fluphenazine increased positive mood ratings but reduced motivation to gamble. Haloperidol effects were stronger when it was received on the first session, while fluphenazine had stronger effects after prior drug-free exposure. Results suggest D1 signaling is central to reward expectancy and motivation to gamble, and that moderate stimulation increases positive affect while reducing motivation to gamble. D1 blockade may also enhance reinforcement of a familiar task by interfering with reward expectancy.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Abnormal movements are clinical symptoms present in neurodegenerative diseases, such Parkinsonism , as well as Tardive dyskinesia. It is thought that unbalance in monoamine levels with their consequent metabolism could be involved in the etiology of these abnormal movements. However, until this moment there is not efficacious treatment with low side effects for these conditions. In this context, Hypericum perforatum (H. perforatum), popularly known as St. John s Wort, is a plant largely used as antidepressant and presenting high amount of polyphenol constituents. Its antidepressant mechanism seems to involve the increase of monoamines and monoaminoxidase inhibition. Here, we evaluated the effect of H. perforatum on different models of abnormal movements in rats, either using fluphenazine or reserpine. It were quantified the number of vacuous chewing movements (VCMs) and locomotor activity (number or rearings and crossings) in both models. In experiment 1, rats received a single administration of fluphenazine enantate (25 mg/Kg, i.m.) and/or H. perforatum (300 mg/Kg, in place of drinking water) during 7 days. Fluphenazine treatment increased VCMs and decreased the locomotor activity after 7 days of treatment. However, H. perforatum did not alter either the number of VCMs or the locomotor activity (represented by number of crossing and rearing in the open field test) in rats. In experiment 2, rats received reserpine administration once a day during 3 days (0.5 mg/Kg, s.c.) and/or H. perforatum (300 mg/Kg, in place of drinking water) during 16 days. Reserpine treatment increased VCMs and decreased the locomotor activity. H. perforatum did not alter the number of VCMs or the number of rearing. However, H. perforatum co-treatment could avoid the effect of reserpine on number of crossings. In conclusion, H. perforatum did not seem to be efficacious to protect against orofacial movements induced by fluphenazine or reserpine in rats. / As desordens motoras são sintomas de doenças neurodegenerativas bem como podem estar associadas ao tratamento com antipsicóticos. Cita-se como exemplo destas desordens, sintomas da Doença de Parkinson (DP) e a Discinesia Tardia (DT), respectivamente. O desequilíbrio cerebral nos níveis de monoaminas e, consequentemente, seu metabolismo tem sido relacionados ao desenvolvimento dos movimentos anormais que aparecem nas desordens motoras, tendo em vista que os circuitos dopaminérgicos estão envolvidos na gênese da DP e da DT. No entanto, ainda não existem tratamentos eficazes e com poucos efeitos colaterais para tais condições. A Hypericum perforatum (H. perforatum), popularmente conhecido como Erva de São João, consiste numa planta amplamente utilizada como antidepressiva e que possui uma grande quantidade de compostos fenólicos, cujo mecanismo para esta atividade está relacionado à inibição da monoamina oxidade (MAO) e da recaptação de monoaminas cerebrais. Assim, o objetivo do presente estudo foi investigar o efeito do H. perforatum em modelos de desordem motora induzida por flufenazina ou reserpina em ratos. Foram quantificados os movimentos de mascar no vazio (MMV) e atividade locomotora (cruzamentos e levantadas observados no teste de campo aberto) em ambos os modelos. No experimento 1, os ratos receberam uma única administração de enantato de flufenazina (25 mg/Kg, i.m.) e ou H. perforatum (300 mg/Kg, no lugar da água de beber) durante 7 dias. O tratamento com flufenazina aumentou o número de MMVs e diminuiu a atividade locomotora em ratos após 7 dias de tratamento. No entanto, o tratamento com H. perforatum não protegeu das alterações comportamentais causadas pelo tratamento com flufenazina. No experimento 2, os ratos receberam água ou H. perforatum (300 mg/Kg, no lugar da água de beber) durante 16 dias. A partir do dia 9 de tratamento os animais receberam uma administração diária de reserpina (0,5 mg/Kg, s.c.) ou veículo durante 3 dias com intervalo de 48 horas. A reserpina aumentou o número MMVs e diminuiu a atividade locomotora em campo aberto. O prétratamento com H. perforatum não alterou o efeito da reserpina sobre o número de MMVs e levantadas. Porém, o pré-tratamento com H. perforatum preveniu o efeito da reserpina sobre número de cruzamentos. Desta forma, podemos concluir que o H. perforatum não apresentou efeito benéfico sobre os movimentos orofaciais induzidos por flufenazina ou reserpina em ratos.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Fluphenazine-induced orofacial dyskinesia (OD) is a putative animal model of tardive dyskinesia (TD) whose pathophysiology has been related to an increase in dopamine hypersensitivity and oxidative stress. Data from literature have shown that patients with TD present a decrease in dopamine transporter (DAT) expression. In a previously study, we have demonstrated that experimental animals presenting high intensity of vacuous chewing movements (VCM) induced by chronic treatment with haloperidol also presented a reduced dopamine uptake into striatum. Considering that one way to regulate DAT is through redox modulation, the first objective of the present study to determine if the chronic treatment with fluphenazine could induce an increase in oxidative stress index in brain regions (striatum and substantia nigra) and an alteration in levels of dopamine uptake in the striatum of rats treated acute and chronically with fluphenazine (Article 1). The fluphenazine treatment produced VCMs in the majority of the treated rats (87% after 24 weeks). Concomitant treatment with diphenyl diselenide decreased the prevalence of VCMs to 50%. Additionally, we separated the rats that developed (+VCM) or did not develop (-VCM) VCMs. We did not find any statistical differences among the groups when oxidative stress parameters were evaluated. Chronic fluphenazine treatment significantly decreased dopamine uptake. Concomitant treatment with diphenyl diselenide was not able to prevent this decrease in those rats that developed VCMs. Another objective of this work was to evaluate the role of dopamine (DA) and other monoamines and their metabolites on acute and chronic of OD induced by fluphenazine in rats (manuscript in preparation 1). The vacuous chewing movements (VCMs) or the levels of monoamines and its metabolites were quantified after 3 (acute) or 24 (chronic) weeks after beginning of treatment. The fluphenazine treatment produced VCMs in part of treated rats (50% after 3 weeks and about 85% after 24 weeks). There were not significant differences between the groups in monoamines levels neither in their metabolites in the striatum under acute fluphenazine treatment in +VCMs rats. However, we observed a trend to increase the levels of the DA metabolites, HVA (p=0.05) and DOPAC (p=0.06), after chronic treatment with fluphenazine. Our data suggest that an increase in DA metabolism could contribute to the maintenance of VCMs in rats. Moreover, development of VCMs seems not to be dependent of DA metabolism. Moreover, the use of diphenyl disselenide seems to be a promissory pharmacological therapy in the reduction of OD prevalence. / A discinesia orofacial (DO) induzida por flufenazina consiste num modelo de discinesia tardia (DT) cuja patofisiologia tem sido relacionada à hipersensibilidade dopaminérgica e ao estresse oxidativo. Dados da literatura demonstraram que pacientes com DT apresentam reduzida expressão do transportador de dopamina (TDA). Em um estudo prévio, nós demonstramos que animais experimentais que apresentam alta intensidade de movimentos de mascar no vazio (MMV) induzidos por tratamento crônico com haloperidol também apresentaram uma redução na captação de dopamina (DA) no estriado. Tendo em vista que uma das maneiras de reduzir a atividade dos TDA é via modulação redox, um primeiro objetivo deste estudo foi determinar se o tratamento crônico com flufenazina poderia induzir um aumento nos índices de estresse oxidativo em regiões cerebrais (estriado e substantia nigra) e quais os efeitos deste tratamento nos níveis de captação de DA no estriado de ratos tratados aguda e cronicamente com flufenazina (Artigo 1). O tratamento com flufenazina produziu MMV na maioria dos ratos tratados (87% após 24 semanas). O tratamento concomitante com disseleneto de difenila diminuiu a prevalência dos MMV para 50%. Além disso, separamos os animais que desenvolveram (+MMV) ou não desenvolveram (-MMV) MMV. Não encontramos nenhuma diferença estatística entre os grupos quando comparados parâmetros de estresse oxidativo. O tratamento crônico, mas não agudo, com flufenazina diminuiu significativamente a captação de DA nos animais que apresentaram MMV. O tratamento concomitante com disseleneto de difenila não foi capaz de prevenir esta redução naqueles ratos que desenvolveram MMV. Um outro objetivo deste trabalho foi avaliar a participação da DA, de outras monoaminas e de seus metabólitos no modelo agudo e crônico de DO induzida por flufenazina em ratos (manuscrito em preparação 1). O tratamento com flufenazina produziu MMV na maioria dos animais tratados (50% após 3 semanas e cerca de 85% após 24 semanas. Não houve diferença estatisticamente significativa entre os grupos controle e tratado com flufenazina agudamente com relação aos níveis de monoaminas e seus metabólitos no estriado de ratos apresentando MMV+. Observamos uma tendência a um aumento nos níveis dos metabólitos da DA, HVA (p=0.05) e DOPAC (p=0.06), após tratamento crônico com flufenazina. Em conjunto, estes resultados indicam que a redução no transporte de DA pode ser um possível mecanismo relacionado à manutenção da DO crônica em ratos. O metabolismo da DA parece ter participação na manutenção da DO, mas não no desenvolvimento. Além disso, o uso do disseleneto de difenila parece ser terapia farmacológica promissora para a redução da prevalência da DO.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Treatment with neuroleptic drugs has been associated to side effects like tardive diskynesia and hepatic damage. In spite of the several reports of hepatotoxicity after neuroleptic administration, few data are available in the literature about these effects and the precise mechanisms by which neuroleptics induce hepatotoxicity remain unclear. In the same way, there are few studies about the effects of neuroleptics on kidney. In this way, the first aim of the present work was to assess the effects of chronic exposure to fluphenazine in liver and kidney of rats, as well as the protective effect of diphenyl diselenide on the fluphenazine-induced damage (article 1). Long-term treatment with fluphenazine caused an increase in lipid peroxidation levels in liver and kidney homogenates, a decrease in hepatic SOD activity, and an increase in hepatic CAT activity. Diphenyl diselenide was able to protect liver and kidney from lipid peroxidation, ameliorate SOD activity in liver, and prevent the increase in hepatic CAT activity. Diphenyl diselenide treatment did not affect δ-ALA-D activity, but fluphenazine and/or in combination with diphenyl diselenide showed an inhibitory effect on δ-ALA-D activity in liver and kidney. The second objective of this study was to determine whether the treatment with haloperidol (HP), valerian or both in association impairs liver or kidney functions (article 2). Valerian did not affect oxidative stress parameters in the liver or kidney of rats. HP only increased glutathione (GSH) depletion in liver, but not in kidney. However, when HP was associated with valerian, an increase in lipid peroxidation levels and reactive species production was observed in the hepatic tissue. HP and valerian when administered independently did not affect the activity of hepatic and renal δ-ALA-D, however, these drugs administered concomitantly provoked an inhibition of hepatic δ-ALA-D activity. Serum aspartate aminotransferase (AST) activity was not altered by any treatment. However, serum alanine aminotransferase (ALT) activity was higher in the HP group and HP plus valerian group. Taken together, these results indicate the relationship between the treatment with flufenazine and the oxidative stress, and also point to the protective role of diphenyl diselenide on the oxidative damage induced by fluphenazine in liver. Our data also suggest adverse interactions between haloperidol and valerian treatments causing hepatic damage related to oxidative stress. / O tratamento com drogas neurolépticas tem sido associado a efeitos colaterais como a discinesia tardia (DT) e o dano hepático. Apesar dos inúmeros casos de hepatotoxicidade após a administração de neurolépticos, são escassos os dados na literatura a respeito desses efeitos e o mecanismo exato pelo qual neurolépticos induzem hepatotoxicidade permanece incerto. Da mesma forma, existem poucos estudos relatando os efeitos dos neurolépticos sobre o rim. Dessa forma, o primeiro objetivo deste trabalho foi avaliar os efeitos da exposição crônica à flufenazina em fígado e rim de ratos bem como o efeito protetor do disseleneto de difenila sobre o dano induzido por flufenazina (artigo 1). O tratamento prolongado com flufenazina causou um aumento na peroxidação lipídica no fígado e no rim, uma diminuição na atividade da SOD hepática, e um aumento na atividade da CAT hepática. O disseleneto de difenila foi capaz de proteger o fígado e o rim da peroxidação lipídica, melhorou a atividade da SOD no fígado, e preveniu o aumento na atividade da CAT no fígado. O tratamento com disseleneto de difenila não afetou a atividade da δ-ALA-D, mas a flufenazina e/ou em combinação com disseleneto de difenila demonstrou ter efeito inibitório sobre a atividade da δ-ALA-D no fígado e no rim. O segundo objetivo deste estudo foi determinar se o tratamento com haloperidol (HP), valeriana ou a associação de ambas as drogas pode alterar as funções hepáticas e renais (artigo 2). A valeriana não afetou nenhum parâmetro de estresse oxidativo no fígado e no rim dos ratos. O HP apenas aumentou a depleção de glutationa (GSH) no fígado, mas não no rim. Entretanto, quando o HP foi associado com a valeriana, um aumento na peroxidação lipídica e produção de espécies reativas foram observados no tecido hepático. HP e valeriana quando administrados independentemente não afetaram a atividade da δ-ALA-D hepática e renal, contudo, quando estas drogas foram administradas concomitantemente provocaram uma inibição da atividade da δ-ALA-D hepática. A atividade da aspartato aminotransferase (AST) do soro não foi alterada por nenhum dos tratamentos. No entanto, a atividade da alanina aminotransferase (ALT) do soro estava aumentada nos grupos tratados com HP e HP mais flufenazina. Juntos estes resultados indicam uma relação entre o tratamento com flufenazina e o estresse oxidativo, e também apontam para o papel protetor do disseleneto de difenila no dano oxidativo induzido por flufenazina no fígado. Nossos dados também sugerem interações adversas no tratamento com haloperidol e valeriana, ocasionando dano hepático associado ao estresse oxidativo.