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The mesolimbic dopamine (DA) system originates in the ventral tegmental area (VTA) and projects to the nucleus accumbens (NAc) and other areas including the basolateral amygdala (BLA), prefrontal cortex, and the hippocampus. Drug use induces reward and leads to dysregulation in these brain areas and eventually to substance use disorders (SUDs). Chapter 1 introduces the mesolimbic DA system and its relationship to drug use and their relevance to each chapter. Chapter 2 explores opioid effects on BLA circuitry which is known to play a role in the emotional response including anxiety and stress in SUDs. We showed that morphine induced an inhibitory effect on GABAergic lateral paracapsular cells (LPCs). These cells inhibit BLA principal neuron output and are influenced by opioids. Opioid activation in LPCs leads to upregulated BLA output, and activation in the NAc and central amygdala which may have important implications for stress/anxiety response for patients with SUDs. Chapter 3 explores the effect of interleukin-10 on the mesolimbic DA system. Specifically, cell-attached recordings of VTA DA neurons increase their firing rate in the presence of IL-10, and in vivo studies showed increased DA release in the NAc. Interleukin-10 receptors were expressed in VTA DA neurons and signals through the phosphoinositide 3-kinase. Surprisingly, IL-10 induced conditioned place aversion in mice which may be related to depression- and anxiety-like behaviors reported by others. Thus, IL-10 appears to be regulating the mesolimbic DA system and its association with reward which may be important in understanding the relationship between inflammation and SUDs. Chapter 4 explores the DA transporter (DAT) kinetics in the presence of psychostimulants using DA iontophoresis. We showed that iontophoretic DA delivery increased DA concentration and clearance rates compared to evoked release making it an important tool in measuring DAT kinetics. Cocaine was bath applied and slowed DAT reuptake at high concentrations and D2 stimulant quinpirole slowed the reuptake process but did not show any effect on DAT trafficking, and D2 antagonist eticlopride showed no change in reuptake or DAT trafficking. Cocaine-injected mice increased locomotion and reduced anxiety-like behavior, and iontophoresis experiments slowed reuptake with bath-applied cocaine. Thus, DA iontophoresis is useful in studying DAT blocker kinetics but has limitations in studying the effects of DAT trafficking. Chapter 5 discusses the impact these studies have on society, the limitations of each chapter, and future directions for this dissertation. Together these studies explore the reward system and its relationship with SUDs. The overarching aim has been to understand the involvement of DA in motivation and reward in the context of SUDs and the influence of opioids, cytokines, and psychostimulants.

Obesity and drug abuse share common neural circuitries including the mesocoticolimbic and striatal dopamine reward system. In the current study, a rat model of diet-induced obesity (DIO) was used to determine striatal dopamine function, impulsivity and motivation as neurobehavioral outcomes and predictors of obesity. For the outcome study, rats were randomly assigned a high-fat (HF) or a low-fat (LF) diet for 8 wk. Following the 8-wk HF-diet exposure, rats were segregated into obesity-prone and obesity-resistant groups based on maximum and minimum body weight gain, respectively, and neurobehavioral outcomes were evaluated. For the predictor study, neurobehavioral antecedents were evaluated prior to an 8-wk high-fat diet exposure and were correlated with subsequent body weight gain. Striatal D2 receptor density was determined by in vitro kinetic analysis of [3H]raclopride binding. DAT function was determined using in vitro kinetic analysis of [3H]dopamine uptake, methamphetamine-evoked [3H]dopamine overflow and no net flux in vivo microdialysis. DAT cell-surface expression was determined using biotinylation and Western blotting. Impulsivity and food-motivated behavior were determined using a delay discounting task and progressive ratio schedule for food-reinforcers, respectively. Relative to obesity-resistant, obesity-prone rats exhibited 18% greater body weight, 42% lower striatal D2 receptor density, 30% lower total DAT expression, 40% lower in vitro and in vivo DAT function, 45% greater extracellular dopamine concentration, and 2-fold greater methamphetamine-evoked [3H]dopamine overflow. Obesity-prone rats exhibited higher motivation for food, but were less impulsive relative to obesity-resistant rats. Neurobehavioral antecedents of DIO included greater motivation for high-fat reinforcers in rats subsequently shown to be obesity-prone relative to obesity-resistant. Impulsivity, DAT function and extracellular dopamine concentration did not predict the DIO-phenotype. Thus, motivation for food is linked to both initiation and maintenance of obesity. Importantly, obesity results in decreased striatal DAT function, which may underlie the maintenance of compulsive food intake in obesity.

Fine temporal regulation of dopamine transmission is critical to its effects on behaviour. Dopamine can be cleared from the synapse either by recycling via the dopamine transporter (DAT) or by enzymatic degradation involving catechol-O-methyltransferase (COMT). DAT recycling predominates in striatum and contributes to dopaminergic regulation of reward-guided behaviour, while COMT degradation predominates in cortex and modulates executive functions. However, human functional imaging studies demonstrate interactive effects of DAT and COMT genotype, suggesting that the traditional division between DAT and COMT is not so clear-cut. Given the interdependence of mesolimbic and mesocortical circuitry and the presence of COMT in the striatum, it is possible that DAT and COMT interact to a greater extent than previously thought. We investigated the contributions of DAT and COMT to regulation of dopamine transmission and reward-guided behaviour by combining in vivo electrochemical recording, pharmacology, and behavioural testing in mice. Using fast scan cyclic voltammetry to record evoked dopamine release in anaesthetised animals, we found that systemic DAT blockade increased the size of dopamine transients in the nucleus accumbens (NAc) but not in the medial frontal cortex (MFC), demonstrating that DAT regulates phasic striatal dopamine release and confirming that DAT makes little contribution to regulation of cortical dopamine transmission. Unexpectedly, COMT inhibition did not affect evoked dopamine transients in either the NAc or the MFC. In agreement with these findings, systemic administration of a DAT blocker, but not of a COMT inhibitor, increased motivation to work for reward in a progressive ratio paradigm. COMT inhibition also had little effect on reinforcement learning (RL) strategies during reward-guided decision making. Intriguingly, however, we found that DAT blockade both decreased the influence of model-free RL and increased the influence of model-based RL on behaviour. Our study confirms that DAT regulates dopamine transmission in striatum but not in cortex and indicates that sub-second changes in dopamine transmission in both regions are largely insensitive to COMT. However, our behavioural data reveal the importance of striatal dopamine in multiple components of reward-guided behaviour, including both motivational aspects traditionally associated with striatum as well as cognitive aspects heretofore mainly associated with cortical function. Together, these findings emphasise that reward processing occurs across corticostriatal circuits and contribute to our understanding of how striatal dopamine transmission regulates reward-guided behaviours.

Effects of pharmacotherapies for Attention Deficit/Hyperactivity Disorder (ADHD) on cocaine abuse liability in ADHD are not understood. Spontaneously Hypertensive Rats (SHR), an ADHD model, exhibited greater cocaine self-administration than control Wistar-Kyoto and Wistar rats. Methylphenidate, but not atomoxetine during adolescence enhanced cocaine self-administration in adult SHRs compared to controls. The mesocortical dopaminergic system, including medial prefrontal (mPFC) and orbitofrontal (OFC) cortices, is important for ADHD and cocaine addiction. Dopamine and norepinephrine transporter (DAT and NET) are molecular targets for methylphenidate, atomoxetine and cocaine action. In the current studies, SHR, Wistar-Kyoto and Wistar were administered methylphenidate (1.5 mg/kg/day, p.o.), atomoxetine (0.3 mg/kg/day, i.p.) or vehicle during adolescence (postnatal day 28-55). During adulthood (>77 days), DAT and NET functions in mPFC and OFC were determined as neurochemical mechanisms and locomotor sensitization to cocaine, and impulsivity under differential reinforcement of low rates 30-second (DRL30) schedule were evaluated as behavioral mechanisms associated with greater cocaine self-administration in methylphenidate-treated SHRs. Maximal velocity of [3H]dopamine uptake (Vmax) by DAT and DAT cellular distribution in mPFC and OFC did not differ between vehicle-control, adult SHR, Wistar-Kyoto and Wistar. Methylphenidate increased DAT Vmax, but not cell-surface expression, in SHR mPFC. In contrast, atomoxetine decreased Vmax and cell-surface expression in SHR OFC. Compared to control strains, norepinephrine uptake by NET in the OFC was increased in vehicle-administered SHR; methylphenidate during adolescence normalized NET function in SHR OFC. Locomotor sensitization was greater in SHR compared to control, and was not altered by methylphenidate. Under DRL30, methylphenidate increased burst responses in adult SHR compared to vehicle control as well as methylphenidate-treated Wistar-Kyoto and Wistar, indicating increased impulsivity. Increased OFC NET function, increased impulsivity and cocaine sensitivity may be the neurobehavioral mechanisms associated with the increased cocaine self-administration in SHR. Increased mPFC DAT function may underlie the enhanced impulsivity and cocaine self-administration in SHR administered methylphenidate during adolescence. Decreased OFC DAT function from atomoxetine-treated SHR may explain the reduced cocaine self-administration relative to methylphenidate. Thus, methylphenidate during adolescence in ADHD may increase risk for cocaine abuse, while atomoxetine may represent a therapeutic alternative for at-risk adolescents with ADHD.

A Doença de Parkinson (DP) é a segunda doença neurodegenerativa mais comum. Atinge 3,3% das pessoas com mais de 64 anos. Com o envelhecimento populacional, sua prevalência deve dobrar. A doença classicamente se caracteriza por degeneração dos neurônios da substantia nigra, afetando principalmente a transmissão dopaminérgica. O tratamento mais eficaz na DP continua sendo a levodopa, um precursor dopaminérgico com excelente resposta motora. Entretanto, à medida que a doença progride, aparece uma série de complicações motoras e não motoras que limitam o tratamento. Para facilitar o reconhecimento destas complicações, foram criados questionários que aumentam a possibilidade de diagnóstico, abordando aspectos motores e não motores. O principal deles é um questionário de 19 itens. Ele consiste em 19 manifestações que o paciente deve assinalar, caso tenha determinado sintoma, e se ele melhora com a próxima dose da medicação. Quando existem pelo menos duas respostas positivas, o questionário tem ótima sensibilidade e especificidade. A Doença de Parkinson tem evolução heterogênea, sendo que uma das causas atribuídas para tal é genética. Tem se estudado muitos genes da rota de dopamina por sua relação íntima com a fisiopatologia e tratamento da doença. O transportador de dopamina (DAT), que realiza a retirada da dopamina da fenda sináptica, desempenha papel fundamental nesta rota. Existe um polimorfismo VNTR com cópias de uma unidade de repetição variando de 3 a 11 com as repetições 9 e 10 sendo os alelos mais comuns. Diversos estudos correlacionaram esse polimorfismo com transtorno do déficit de atenção e hiperatividade quando há 10 repetições e com a Doença de Parkinson quando há 9 repetições. Seria um candidato ideal para avaliação com relação às complicações do tratamento e progressão. Assim, avaliamos pacientes com Doença de Parkinson longitudinalmente para comparar a progressão da doença com polimorfismo do DAT e verificar as complicações associadas ao tratamento. Inicialmente, realizamos uma revisão sistemática das propriedades clinimétricas dos questionários de wearing off. Esta revisão mostrou que o questionário de 9 itens tem sensibilidade de 0,87-1 e especificidade de 0,1-0,69. Já o questionário de 19 itens tem sensibilidade de 0,81-0,9 e especificidade de 0,63-0,8 com ponto de corte igual a 2 itens positivos. Realizamos a validação deste último para português, com boa estabilidade no teste-reteste com correlação intraclasse de 0,87 (IC 95% 0,69-0,95 p < 0,01) e sensibilidade de 0,97 (IC 95% 0,94-1 p < 0,01) e especificidade de 0,71 (IC 95% 0,56-0,85 p < 0,01). Para progressão, foi demonstrada uma associação de sexo feminino e a presença de alelo com 9 repetições como fatores de risco para progressão mais rápida. A progressão em homens medida pelo UPDRS 3 era menor em 1,277 (IC 95% 2,18-0,38 p < 0,01) e pelo UPDRS total era menor em 1,50 (IC 95% 2,92-0,11 p = 0,031). Com presença de alelo com 9 repetições, a progressão do UPDRS 3 era menor em 1,92 (ICC 95% 0,04-1,01 p = 0,0317), e presente mesmo controlando para sexo. Não houve diferença na escala de discinesias ou questionário wearing off. Assim, os resultados obtidos mostraram que o questionário de 19 itens é uma boa ferramenta diagnóstica, sendo validado para português. Além disso, o polimorfismo DAT está associado à progressão mais rápida da DP com 9 repetições. / Parkinson’s disease (PD) is the second most common neurodegenerative disease. It affects 3.3% of people over 64 years. With population aging, its prevalence should double. The disease is classically characterized by degeneration of substantia nigra neurons, mainly affecting dopaminergic transmission. The most effective treatment for PD continues to be levodopa, a dopaminergic precursor with excellent motor response. However, as the disease progresses, there is a number of motor and non-motor complications that limits the treatment. To facilitate the recognition of these complications, questionnaires were created to increase the possibility of diagnosis, addressing motor and non-motor aspects. The main one is a questionnaire of 19 items. It consists of 19 symptoms that the patients should indicate, if they feel particular symptom, and if they get better with the next dose of medication. When there are at least two positive responses, the questionnaire has optimal sensitivity and specificity. Parkinson’s disease has a heterogeneous evolution, and one of the reasons attributed for that is genetic. Many genes of the dopamine route have been studied for their intimate relationship with the pathophysiology and treatment of the disease. The dopamine transporter, with synaptic cleft reuptake, plays a key role in this route. It has a VNTR polymorphism with copies of a repeating unit ranging from 3 to 11 with repetitions 9 and 10 being the most common alleles. Several studies correlated this polymorphism with Attention Deficit Hyperactivity Disorder with 10 repetition allele and Parkinson’s disease with 9 repetition alleles. It would be an ideal candidate for evaluation regarding treatment complications and progression. Thus, we evaluated patients with Parkinson’s disease longitudinally to compare disease progression with DAT polymorphism and to verify treatment-related complications. Initially we performed a systematic review of the clinimetric properties of the wearing off questionnaires. That showed that the questionnaire of 9 items has sensitivity of 0.87-1 and specificity of 01-0.69. The questionnaire of 19 items has a sensitivity of 0.81-0.9 and a specificity of 0.63-0.8 with a cut-off point of 2 items. We performed the validation of the latter for Portuguese, with good stability in the testretest with intraclass correlation of 0.87 (95% CI 0.69-0.95 p < 0.01) and sensitivity of 0.97 (CI 95% 0.94-1 p < 0.01) and specificity of 0.71 (95% CI 0.56-0.85 p < 0.01). We demonstrated a female association and presence of 9 DAT allele repetition as risk factors for faster progression. The progression in men ofwith UPDRS 3 was lower in 1.277 (95% CI 2.18-0.38 p < 0.01) and total UPDRS was lower in 1.50 (95% CI 2.92-0.11 p = 0.031). With the presence of allele with 9 repetitions the progression of UPDRS 3 was lower in 1.92 (ICC 95% 0.04-1.01 p = 0.0317), and present even correcting sex. There was no difference in the dyskinesia scale or wearing off questionnaire. Thus, the results obtained showed wearing off questionnaire is a good tool for clinical and research, and it is validated to Portuguese. Also, DAT polymorphism is associated with faster PD progression with 9 repetition allele.

A Doença de Parkinson (DP) é a segunda doença neurodegenerativa mais comum. Atinge 3,3% das pessoas com mais de 64 anos. Com o envelhecimento populacional, sua prevalência deve dobrar. A doença classicamente se caracteriza por degeneração dos neurônios da substantia nigra, afetando principalmente a transmissão dopaminérgica. O tratamento mais eficaz na DP continua sendo a levodopa, um precursor dopaminérgico com excelente resposta motora. Entretanto, à medida que a doença progride, aparece uma série de complicações motoras e não motoras que limitam o tratamento. Para facilitar o reconhecimento destas complicações, foram criados questionários que aumentam a possibilidade de diagnóstico, abordando aspectos motores e não motores. O principal deles é um questionário de 19 itens. Ele consiste em 19 manifestações que o paciente deve assinalar, caso tenha determinado sintoma, e se ele melhora com a próxima dose da medicação. Quando existem pelo menos duas respostas positivas, o questionário tem ótima sensibilidade e especificidade. A Doença de Parkinson tem evolução heterogênea, sendo que uma das causas atribuídas para tal é genética. Tem se estudado muitos genes da rota de dopamina por sua relação íntima com a fisiopatologia e tratamento da doença. O transportador de dopamina (DAT), que realiza a retirada da dopamina da fenda sináptica, desempenha papel fundamental nesta rota. Existe um polimorfismo VNTR com cópias de uma unidade de repetição variando de 3 a 11 com as repetições 9 e 10 sendo os alelos mais comuns. Diversos estudos correlacionaram esse polimorfismo com transtorno do déficit de atenção e hiperatividade quando há 10 repetições e com a Doença de Parkinson quando há 9 repetições. Seria um candidato ideal para avaliação com relação às complicações do tratamento e progressão. Assim, avaliamos pacientes com Doença de Parkinson longitudinalmente para comparar a progressão da doença com polimorfismo do DAT e verificar as complicações associadas ao tratamento. Inicialmente, realizamos uma revisão sistemática das propriedades clinimétricas dos questionários de wearing off. Esta revisão mostrou que o questionário de 9 itens tem sensibilidade de 0,87-1 e especificidade de 0,1-0,69. Já o questionário de 19 itens tem sensibilidade de 0,81-0,9 e especificidade de 0,63-0,8 com ponto de corte igual a 2 itens positivos. Realizamos a validação deste último para português, com boa estabilidade no teste-reteste com correlação intraclasse de 0,87 (IC 95% 0,69-0,95 p < 0,01) e sensibilidade de 0,97 (IC 95% 0,94-1 p < 0,01) e especificidade de 0,71 (IC 95% 0,56-0,85 p < 0,01). Para progressão, foi demonstrada uma associação de sexo feminino e a presença de alelo com 9 repetições como fatores de risco para progressão mais rápida. A progressão em homens medida pelo UPDRS 3 era menor em 1,277 (IC 95% 2,18-0,38 p < 0,01) e pelo UPDRS total era menor em 1,50 (IC 95% 2,92-0,11 p = 0,031). Com presença de alelo com 9 repetições, a progressão do UPDRS 3 era menor em 1,92 (ICC 95% 0,04-1,01 p = 0,0317), e presente mesmo controlando para sexo. Não houve diferença na escala de discinesias ou questionário wearing off. Assim, os resultados obtidos mostraram que o questionário de 19 itens é uma boa ferramenta diagnóstica, sendo validado para português. Além disso, o polimorfismo DAT está associado à progressão mais rápida da DP com 9 repetições. / Parkinson’s disease (PD) is the second most common neurodegenerative disease. It affects 3.3% of people over 64 years. With population aging, its prevalence should double. The disease is classically characterized by degeneration of substantia nigra neurons, mainly affecting dopaminergic transmission. The most effective treatment for PD continues to be levodopa, a dopaminergic precursor with excellent motor response. However, as the disease progresses, there is a number of motor and non-motor complications that limits the treatment. To facilitate the recognition of these complications, questionnaires were created to increase the possibility of diagnosis, addressing motor and non-motor aspects. The main one is a questionnaire of 19 items. It consists of 19 symptoms that the patients should indicate, if they feel particular symptom, and if they get better with the next dose of medication. When there are at least two positive responses, the questionnaire has optimal sensitivity and specificity. Parkinson’s disease has a heterogeneous evolution, and one of the reasons attributed for that is genetic. Many genes of the dopamine route have been studied for their intimate relationship with the pathophysiology and treatment of the disease. The dopamine transporter, with synaptic cleft reuptake, plays a key role in this route. It has a VNTR polymorphism with copies of a repeating unit ranging from 3 to 11 with repetitions 9 and 10 being the most common alleles. Several studies correlated this polymorphism with Attention Deficit Hyperactivity Disorder with 10 repetition allele and Parkinson’s disease with 9 repetition alleles. It would be an ideal candidate for evaluation regarding treatment complications and progression. Thus, we evaluated patients with Parkinson’s disease longitudinally to compare disease progression with DAT polymorphism and to verify treatment-related complications. Initially we performed a systematic review of the clinimetric properties of the wearing off questionnaires. That showed that the questionnaire of 9 items has sensitivity of 0.87-1 and specificity of 01-0.69. The questionnaire of 19 items has a sensitivity of 0.81-0.9 and a specificity of 0.63-0.8 with a cut-off point of 2 items. We performed the validation of the latter for Portuguese, with good stability in the testretest with intraclass correlation of 0.87 (95% CI 0.69-0.95 p < 0.01) and sensitivity of 0.97 (CI 95% 0.94-1 p < 0.01) and specificity of 0.71 (95% CI 0.56-0.85 p < 0.01). We demonstrated a female association and presence of 9 DAT allele repetition as risk factors for faster progression. The progression in men ofwith UPDRS 3 was lower in 1.277 (95% CI 2.18-0.38 p < 0.01) and total UPDRS was lower in 1.50 (95% CI 2.92-0.11 p = 0.031). With the presence of allele with 9 repetitions the progression of UPDRS 3 was lower in 1.92 (ICC 95% 0.04-1.01 p = 0.0317), and present even correcting sex. There was no difference in the dyskinesia scale or wearing off questionnaire. Thus, the results obtained showed wearing off questionnaire is a good tool for clinical and research, and it is validated to Portuguese. Also, DAT polymorphism is associated with faster PD progression with 9 repetition allele.

A Doença de Parkinson (DP) é a segunda doença neurodegenerativa mais comum. Atinge 3,3% das pessoas com mais de 64 anos. Com o envelhecimento populacional, sua prevalência deve dobrar. A doença classicamente se caracteriza por degeneração dos neurônios da substantia nigra, afetando principalmente a transmissão dopaminérgica. O tratamento mais eficaz na DP continua sendo a levodopa, um precursor dopaminérgico com excelente resposta motora. Entretanto, à medida que a doença progride, aparece uma série de complicações motoras e não motoras que limitam o tratamento. Para facilitar o reconhecimento destas complicações, foram criados questionários que aumentam a possibilidade de diagnóstico, abordando aspectos motores e não motores. O principal deles é um questionário de 19 itens. Ele consiste em 19 manifestações que o paciente deve assinalar, caso tenha determinado sintoma, e se ele melhora com a próxima dose da medicação. Quando existem pelo menos duas respostas positivas, o questionário tem ótima sensibilidade e especificidade. A Doença de Parkinson tem evolução heterogênea, sendo que uma das causas atribuídas para tal é genética. Tem se estudado muitos genes da rota de dopamina por sua relação íntima com a fisiopatologia e tratamento da doença. O transportador de dopamina (DAT), que realiza a retirada da dopamina da fenda sináptica, desempenha papel fundamental nesta rota. Existe um polimorfismo VNTR com cópias de uma unidade de repetição variando de 3 a 11 com as repetições 9 e 10 sendo os alelos mais comuns. Diversos estudos correlacionaram esse polimorfismo com transtorno do déficit de atenção e hiperatividade quando há 10 repetições e com a Doença de Parkinson quando há 9 repetições. Seria um candidato ideal para avaliação com relação às complicações do tratamento e progressão. Assim, avaliamos pacientes com Doença de Parkinson longitudinalmente para comparar a progressão da doença com polimorfismo do DAT e verificar as complicações associadas ao tratamento. Inicialmente, realizamos uma revisão sistemática das propriedades clinimétricas dos questionários de wearing off. Esta revisão mostrou que o questionário de 9 itens tem sensibilidade de 0,87-1 e especificidade de 0,1-0,69. Já o questionário de 19 itens tem sensibilidade de 0,81-0,9 e especificidade de 0,63-0,8 com ponto de corte igual a 2 itens positivos. Realizamos a validação deste último para português, com boa estabilidade no teste-reteste com correlação intraclasse de 0,87 (IC 95% 0,69-0,95 p < 0,01) e sensibilidade de 0,97 (IC 95% 0,94-1 p < 0,01) e especificidade de 0,71 (IC 95% 0,56-0,85 p < 0,01). Para progressão, foi demonstrada uma associação de sexo feminino e a presença de alelo com 9 repetições como fatores de risco para progressão mais rápida. A progressão em homens medida pelo UPDRS 3 era menor em 1,277 (IC 95% 2,18-0,38 p < 0,01) e pelo UPDRS total era menor em 1,50 (IC 95% 2,92-0,11 p = 0,031). Com presença de alelo com 9 repetições, a progressão do UPDRS 3 era menor em 1,92 (ICC 95% 0,04-1,01 p = 0,0317), e presente mesmo controlando para sexo. Não houve diferença na escala de discinesias ou questionário wearing off. Assim, os resultados obtidos mostraram que o questionário de 19 itens é uma boa ferramenta diagnóstica, sendo validado para português. Além disso, o polimorfismo DAT está associado à progressão mais rápida da DP com 9 repetições. / Parkinson’s disease (PD) is the second most common neurodegenerative disease. It affects 3.3% of people over 64 years. With population aging, its prevalence should double. The disease is classically characterized by degeneration of substantia nigra neurons, mainly affecting dopaminergic transmission. The most effective treatment for PD continues to be levodopa, a dopaminergic precursor with excellent motor response. However, as the disease progresses, there is a number of motor and non-motor complications that limits the treatment. To facilitate the recognition of these complications, questionnaires were created to increase the possibility of diagnosis, addressing motor and non-motor aspects. The main one is a questionnaire of 19 items. It consists of 19 symptoms that the patients should indicate, if they feel particular symptom, and if they get better with the next dose of medication. When there are at least two positive responses, the questionnaire has optimal sensitivity and specificity. Parkinson’s disease has a heterogeneous evolution, and one of the reasons attributed for that is genetic. Many genes of the dopamine route have been studied for their intimate relationship with the pathophysiology and treatment of the disease. The dopamine transporter, with synaptic cleft reuptake, plays a key role in this route. It has a VNTR polymorphism with copies of a repeating unit ranging from 3 to 11 with repetitions 9 and 10 being the most common alleles. Several studies correlated this polymorphism with Attention Deficit Hyperactivity Disorder with 10 repetition allele and Parkinson’s disease with 9 repetition alleles. It would be an ideal candidate for evaluation regarding treatment complications and progression. Thus, we evaluated patients with Parkinson’s disease longitudinally to compare disease progression with DAT polymorphism and to verify treatment-related complications. Initially we performed a systematic review of the clinimetric properties of the wearing off questionnaires. That showed that the questionnaire of 9 items has sensitivity of 0.87-1 and specificity of 01-0.69. The questionnaire of 19 items has a sensitivity of 0.81-0.9 and a specificity of 0.63-0.8 with a cut-off point of 2 items. We performed the validation of the latter for Portuguese, with good stability in the testretest with intraclass correlation of 0.87 (95% CI 0.69-0.95 p < 0.01) and sensitivity of 0.97 (CI 95% 0.94-1 p < 0.01) and specificity of 0.71 (95% CI 0.56-0.85 p < 0.01). We demonstrated a female association and presence of 9 DAT allele repetition as risk factors for faster progression. The progression in men ofwith UPDRS 3 was lower in 1.277 (95% CI 2.18-0.38 p < 0.01) and total UPDRS was lower in 1.50 (95% CI 2.92-0.11 p = 0.031). With the presence of allele with 9 repetitions the progression of UPDRS 3 was lower in 1.92 (ICC 95% 0.04-1.01 p = 0.0317), and present even correcting sex. There was no difference in the dyskinesia scale or wearing off questionnaire. Thus, the results obtained showed wearing off questionnaire is a good tool for clinical and research, and it is validated to Portuguese. Also, DAT polymorphism is associated with faster PD progression with 9 repetition allele.

The synthetic cathinones, 3,4- methylenedioxypyrovalerone (MDPV), 4-methylmethcathinone (mephedrone), and 3,4- methylenedioxymethcathinone (methylone), gained worldwide notoriety as the psychoactive components of ‘bath salts;’ a marketing term used to circumvent federal drug laws and permit their legal sale. Previous studies have shown that these drugs share pharmacological characteristics with cocaine and the amphetamines, however, descriptions of their neurotoxic properties are limited. Moreover, while forensic analysis has revealed that the most frequently abused bath salts ‘brands’ contain binary and ternary mixtures of MDPV, mephedrone, and methylone, the majority of preclinical research has focused on explicating the individual effects of these drugs. Therefore, the present dissertation aimed to address this limitation and characterize the acute and chronic effects of combined synthetic cathinone exposure on dopaminergic tone in mesolimbic and nigrostriatal brain regions. To accomplish this, male Swiss-Webster mice were administered MDPV, mephedrone, and methylone, individually or concomitantly, 1 time or 7 times over the course of two weeks and the corresponding effects of each treatment on mesolimbic and nigrostriatal brain tissue levels of dopamine (DA) and DA metabolites were analyzed using a high performance liquid chromatography – electrochemical detection (HPLC-ECD) assay. Additionally, motor-stimulant activity was evaluated after both dosing regimens using locomotor activity assays, while immunoblot and immunostaining techniques were used to evaluate the chronic effects of co-synthetic cathinone exposure on tissue levels of tyrosine hydroxylase (TH), dopamine transporter (DAT), monoamine oxidase B (MAO-B), catechol-O-methyltransferase (COMT), and glial fibrillary acidic protein (GFAP). Results from these studies provide evidence of a significant pharmacological interaction among major bath salt constituents, MDPV, mephedrone, and methylone. This was observed acutely as enhanced DA responses and chronically as functional toxicity at the DA synapse. Furthermore, such interactions may contribute to the deleterious effects reported by bath salt users. Together, these findings have shown that the composition of bath salts preparations can significantly influence their psychostimulant and toxic effects, substantiating the importance of modeling bath salts as drug mixtures.