ABSTRACT
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 microg/microl, 5.0 microg/microl or 10.0 microg/microl) 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 microg/microl, P < 0.05; 10.0 microg/microl, 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 microg/microl, 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.
Subject(s)
Estrus/drug effects , Pyridines/pharmacology , Receptors, Metabotropic Glutamate/antagonists & inhibitors , Thiazoles/pharmacology , Animals , Behavior, Animal , Brain/anatomy & histology , Brain/metabolism , Conditioning, Operant , Conflict, Psychological , Dose-Response Relationship, Drug , Female , Rats , Rats, Wistar , Receptor, Metabotropic Glutamate 5 , Septal Nuclei/pathologyABSTRACT
Anticonflict-like effects of aqueous extract of flowers of Achillea millefolium L., a plant with purported anxiolytic actions, were studied in female Wistar rats during late proestrus or diestrus. During late proestrus (p < 0.05), control rats displayed reduced conflict behavior compared with diestrus. Diazepam (2.0 mg/kg; i.p.) reduced conflict behavior both during late proestrus (p < 0.05) or diestrus (p < 0.05). Doses of 8.0 mg/kg (p < 0.05), 10.0 mg/kg (p < 0.05) or 12.0 mg/kg (p < 0.05) of Achillea millefolium reduced conflict behavior during late proestrus. Conversely, during diestrus, only the dose of 12.0 mg/kg (p < 0.05) of Achillea millefolium L. reduced conflict behavior. In conclusion, the anticonflict-like actions of Achillea millefolium L. may vary according to the estrous cycle phase.
Subject(s)
Achillea , Agonistic Behavior/drug effects , Anti-Anxiety Agents/pharmacology , Behavior, Animal/drug effects , Phytotherapy , Plant Extracts/pharmacology , Animals , Anti-Anxiety Agents/administration & dosage , Anti-Anxiety Agents/therapeutic use , Estrous Cycle , Female , Flowers , Plant Extracts/administration & dosage , Plant Extracts/therapeutic use , Rats , Rats, WistarABSTRACT
The aim of the present study was to test the hypothesis that allopregnanolone infused into the lateral septal nuclei will reduce conflict-like behavior in ovariectomized rats. The interaction with systemic administration of several agonists and antagonists of the GABA-A receptor was assessed. Results showed that intralateral septal doses of allopregnanolone (1.0 microg, P<.05; 2.0 microg, P<.05) or systemic injections of allopregnanolone (1.0 mg/kg s.c., P<.05; 2.0 mg/kg s.c., P<.05), diazepam (2.0 mg/kg i.p., P<.05), or muscimol (0.3 mg/kg i.p., P<.05; 0.6 mg/kg i.p., P<.05) reduced conflict-like behavior. Subthreshold doses of intralateral septal infusions of allopregnanolone (0.5 microg/side) synergized with systemic subthreshold doses of GABA-A agonists: allopregnanolone (0.5 mg/kg, P<.05), diazepam (1.5 mg/kg, P<.05), or muscimol (0.1 mg/kg, P<.05). The GABA-A antagonists, flumazenil (0.1 mg/kg i.p.) and bicuculline (2.0 mg/kg i.p.) attenuated the synergism between intralateral septal infusions of allopregnanolone and diazepam or muscimol, respectively. Conversely, neither flumazenil (P<.05) nor bicuculline (P<.05) attenuated the synergism of the combination allopregnanolone (intralateral septum nuclei; 0.5 microg/side) plus systemic injections of allopregnanolone. In conclusion, allopregnanolone reduced conflict-like behavior probably acting at the GABA-A receptors found in the lateral septal nuclei.
