Interação entre adenosina, dopamina e óxido nítrico nos núcleos basais : análise do comportamento motor em um modelo animal da doença de Parkinson

Abstract

Introduction: Dopamine, adenosine and nitric oxide (NO) perform an important role in the brain’s basal nuclei function. However, the interaction between these, in the motor behavior modulation still not well clarified. Aims: Evaluate the interaction between the dopamine, adenosine and nitric oxide in the basal nuclei, through the evaluation of the motor behavior, in an animal model of Parkinson disease. Material and Methods: Animals and experimental groups of Swiss mice (n=272), male, weighting between 20 and 30 gr. Experiment I: The animals received an intraperitoneal injection (i.p.) of saline or caffeine, followed by the (i.p.) injection of saline or L-Arginina, haloperidol, L-NOARG or L-NAME after 30 minutes, coming to a total of 5 experimental groups. Experiment II: The animals received an (i.p.) injection of saline or NECA (5’, N-Etilcarboxamidoadenosine), followed by an (i.p.) injection of saline or L-Arginina, or haloperidol or L-NOARG or L-NAME after 30 minutes, coming to a total of 5 experimental groups. After breaks of 30, 60 and 90 minutes subsequent the drugs application, the animals were submitted to a functional evaluation in the catalepsy test and open field test. Statistical Analysis: The obtained results were analyzed by the SigmaStat software for Windows, version 2.0 The averages of treatment and time factors were compared by Two Way Repeated Measures ANOVA test. The comparison between the experimental groups, related to catalepsy time variables, the walked quadrant and raising, were done through an One Way Repeated Measures ANOVA test followed by Duncan post test. The comparison of the analysis moments, related to the catalepsy time was done through the One Way Repeated Measures test followed by the Duncan post test. In all these tests was considered a significant level of 5%. Results: The antagonism of the dopamine receptors, with haloperidol, and the inhibition of the nitric oxide synthase, with L-NOARG, caused catalepsy and hipolocomotion in the animals, and these motor behavior were partly reverted by caffeine, which is a non selective adenosine receptor. The agonist of adenosine receptors NECA took the inverse motor effects to those observed by the caffeine application, causing catalepsy and hipolocomotion in the animals. Besides that, NECA potentiated the action of haloperidol and L-NOARG. Conclusion: The modulation of the motor behavior is influenced by the action and interaction of many neurotransmitters and it goes further the dopamine action, in the brain’s basis nucleus. The observations of this study corroborates with the hypothesis of an inhibition action of the adenosine upon the D2 receptors of dopamine and suggest an close interaction between dopamine, nitric oxide and adenosine and brain’s basis nucleus.