RESUMO
Previous experimental data from this laboratory demonstrated the participation of the striatum and dopaminergic pathways in central nociceptive processing. The objective of this study was to examine the possible pathways and neural structures associated with the analgesic action of the striatum. The experiments were carried out in rats anesthetized with urethane. The jaw-opening reflex (JOR) was evoked by electrical stimulation of the tooth pulp of lower incisors and recorded in the anterior belly of the digastric muscles. Intrastriatal microinjection of apomorphine, a nonspecific dopamine agonist, reduced or abolished the JOR amplitude. Electrolytic or kainic acid lesions, unilateral to the apomorphine-injected striatum, of the globus pallidus, substantia nigra pars reticulata, subthalamic nucleus and bilateral lesion the rostroventromedial medulla (RVM), blocked the inhibition of the JOR by striatal stimulation. These findings suggest that the main output nuclei of the striatum and the RVM may be critical elements in the neural pathways mediating the inhibition of the reflex response, evoked in jaw muscles by noxious stimulation of dental pulp.
Assuntos
Corpo Estriado/fisiologia , Arcada Osseodentária/fisiologia , Reflexo/fisiologia , Animais , Apomorfina/administração & dosagem , Apomorfina/farmacologia , Encéfalo/efeitos dos fármacos , Encéfalo/fisiologia , Corpo Estriado/efeitos dos fármacos , Polpa Dentária/fisiologia , Agonistas de Dopamina/administração & dosagem , Agonistas de Dopamina/farmacologia , Estimulação Elétrica , Eletromiografia , Agonistas de Aminoácidos Excitatórios/toxicidade , Ácido Caínico/toxicidade , Masculino , Microinjeções , Músculos/fisiologia , Vias Neurais/efeitos dos fármacos , Vias Neurais/fisiologia , Ratos , Ratos Sprague-Dawley , Reflexo/efeitos dos fármacos , Fatores de Tempo , UretanaRESUMO
1. The aim of this mini-review was to describe an underrecognized but important aspect of the basal ganglia diseases, the dysfunction of the autonomic nervous system that patients suffer owing to the degenerative process affecting these structures, mainly Parkinson's disease. 2. We analyze the most prevalent autonomic abnormalities in these patients from an experimental and clinical point of view.
