Influence of stressful events on the catalepsy induced by intraperitoneal administration of haloperidol in rats

Abstract

Catalepsy is a condition characterized by varying degrees of muscle rigidity and low flexibility, resulting in an immobile state in which the individual is not able to change externally imposed postures. This condition can be induced by the administration of haloperidol, a neuroleptic drug widely used in the treatment of schizophrenia. Haloperidol is a potent antagonist of dopaminergic D2 receptors and its action in the nigrostriatal pathway can cause various adverse effects, among them catalepsy. The pattern of the muscular rigidity of haloperidol-induced catalepsy, observed by electromyography, is very similar to the pattern observed in Parkinson's disease; so this condition makes it a good model to study the parkinsonian rigidity. Parkinson seems to have many of its symptoms dependent on the emotional state of the patient, so it is possible that there is some relationship between the emotional state and the cataleptic state of animals treated with haloperidol. Knowing the clinical reports of an emotional influence on the motor aspect of Parkinson's patients and in view of the importance of research of biological changes involved in mental disorders associated with stress, the current work aims to continue the evaluation of the influence of stressful events on the cataleptic state of rats treated with haloperidol. For this, different groups of animals will be exposed to elevated plus-maze test, to the confinement in the open arm of the maze, or will receive corticosterone administration. To evaluate the cataleptic state, animals will be submitted to catalepsy tests 15, 30, 45, 60, 75 and 90 min after haloperidol administration. (AU)