Estrus variation in anticonflict-like effects of the mGlu5 receptor antagonist MTEP, microinjected into lateral septal nuclei of female Wistar rats

Anticonflict-like effects of the mGlu5 receptor antagonist MTEP (systemic administrations: 1.50, 3.0 or 6.0 mg/kg; i.p.; intra-lateral septal nuclei or intra-medial septal region infusions: 2.5 μg/μl, 5.0 μg/μl or 10.0 μg/μl) were assessed in Wistar rats during late proestrus or metestrus–diestrus. Results showed that control rats displayed an increased number of immediately punished reinforcers during late proestrus (P < 0.05), when compared to metestrus–diestrus. During late proestrus, systemic administrations (3.0 mg/kg, P < 0.05; 6.0 mg/kg P < 0.05) or intra-lateral septal nuclei infusions (5.0 μg/μl, P < 0.05; 10.0 μg/μl, P < 0.05) of MTEP increased the number of immediately punished reinforcers received. During metestrus–diestrus only the highest doses of MTEP (systemic administration: 6.0 mg/kg P < 0.05; intra-lateral septal nuclei infusions: 10.0 μg/μl, P < 0.05) increased the number of immediately punished reinforcers obtained. MTEP infusions into the medial septum produced neither of these anticonflict effects. In conclusion, data showed an estrus variation in those anticonflict-like effects of the mGlu5 receptor antagonist MTEP, systemically administered or microinjected into lateral septal nuclei of female Wistar rats.