Efeitos da meta-clorofenilpiperazina (mCPP) avaliados no teste de catalepsia em ratos machos e fêmeas

Abstract

Meta-chlorophenylpiperazine (mCPP) is a synthetic non-selective agonist of serotoninergic receptors, which has been used in the study of several psychopathologies such as Obsessive-Compulsive Disorder (OCD). In these studies, mCPP has demonstrated motor effects of increasing or decreasing locomotor activity in animals in a dose-dependent manner and probably due to an interaction between the 5-HT2C serotonergic receptors and their regulation of dopaminergic neurotransmission. Some studies carried out with females have shown a possible influence of the estrous cycle on the effects of mCPP. However, more studies are necessary to further understand such differences. The present study aimed to evaluate whether mCPP induces catalepsy in Wistar rats, and to verify if there are differences in the results presented between male and female rats in different phases of the estrous cycle. For this, Wistar rats were used, 72 males and 77 females, weighing approximately 250 g. The animals received saline (control) or mCPP in the doses of 0.1 mg/kg, 1.0 mg/kg, 3.0 mg/kg, and 10 mg/kg, and the positive control group received haloperidol (dopamine D2-like receptor antagonist) at a dose of 1.0 mg/kg. After administration, every 10 min, a catalepsy test was performed, totaling 6 tests. Haloperidol was able to induce catalepsy in both males and females. The cataleptic effect of haloperidol was dependent on the phase of the estrous cycle in females, being observed in metestrus/diestrus females, but not in those tested in proestrus/estrus. mCPP, on the other hand, did not cause catalepsy in males or females, regardless of the phase of the estrous cycle. The results obtained with mCPP suggest that the motor alterations observed in previous studies are different from those that characterize cataleptic states. Such findings are important in the context of using mCPP for the study of OCD and indicate that the assessment of mCPP-induced compulsive-like behaviors would not be impaired by drug-induced cataleptic effects.