Antidepressant-like actions of intra-accumbens infusions of allopregnanolone in ovariectomized Wistar rats.

This study was aimed to verify the role of the nucleus accumbens (NAcc) in the antidepressant-like effects of allopregnanolone in ovariectomized rats forced to swim. The interaction between infusions of allopregnanolone (intra-NAcc) with systemic administrations of allopregnanolone, muscimol, fluoxetine and GABA-A antagonists was assessed. Results showed that allopregnanolone (intra-NAcc; 1.5 microg, p < 0.05; 2.0 microg, p < 0.05) or systemic injections of allopregnanolone (1.5 mg/kg, p < 0.05; 2.0 mg/kg, p < 0.05; s.c.) or muscimol (0.3 mg/kg, p < 0.05; 0.6 mg/kg, p < 0.05; i.p.) reduced immobility by increasing climbing in the forced swimming task (FST), whereas fluoxetine (1.0 mg/kg, p < 0.05; 2.0 mg/kg, p < 0.05; i.p.) reduced immobility by increasing swimming. Allopregnanolone (intra-NAcc; 0.5 microg/side) synergized with systemic doses of allopregnanolone (0.5 mg/kg; p < 0.05), muscimol (0.1 mg/kg; p < 0.05) or fluoxetine (0.5 mg/kg; p < 0.05) and reduced immobility by increasing climbing. Picrotoxin (0.125 mg/kg; i.p.) attenuated the synergism of the combination allopregnanolone (intra-NAcc; 0.5 microg/side) plus fluoxetine (i.p.) or allopregnanolone (s.c.) and the effects of allopregnanolone (intra-NAcc; 1.5 microg/side). Bicuculline (2.0 mg/kg; i.p.) attenuated the synergism between the combination allopregnanolone (intra-NAcc; 0.5 microg/side) plus muscimol (i.p.), but not the synergism of the combination allopregnanolone (intra-NAcc; 0.5 microg/side) plus allopregnanolone (s.c.). In conclusion, allopregnanolone (systemic injections or intra-NAcc), fluoxetine or muscimol produced antidepressant-like effects in the FST. Subthreshold doses of allopregnanolone (intra-NAcc) synergized with systemic subthreshold doses of fluoxetine, muscimol or allopregnanolone. Antagonists of the GABA-A receptor canceled the synergism.

Anxiolytic-like actions of leaves of Casimiroa edulis (Rutaceae) in male Wistar rats.

Anxiolytic-like actions of an aqueous extract of the leaves of Casimiroa edulis (Ce) La Llave ex Lex. (Rutaceae) were studied in male Wistar rats in the elevated plus-maze test, whether effect on locomotion were studied in the open-field task, and its possible antidepressant-like actions in the forced swimming task. In the elevated plus-maze test, diazepam (Dz) (1.30 mg/kg; P < 0.05) and Casimiroa edulis (25.0 mg/kg, P < 0.05; 35.0 mg/kg, P < 0.05) increased open arms exploration (i.e., anxiolytic-like action). Doses of 45.0 mg/kg (P < 0.05) and 55.0 mg/kg (P < 0.05) of Casimiroa edulis reduced locomotion in the elevated plus-maze test and in the open-field test. In the forced swimming task, desipramine (dmi) (32.0 mg/kg; P < 0.05) reduced immobility (i.e., antidepressant-like action). Conversely, as compared to control rats, neither diazepam (Dz) (1.30 mg/kg) nor Casimiroa edulis (25.0 mg/kg) modified immobility in the forced swimming task. However, diazepam (P < 0.05) or Casimiroa edulis (P < 0.05), when co-administered, canceled the antiimmobility actions of desipramine. In conclusion, the leaves of Casimiroa edulis (Rutaceae) produced anxiolytic-like actions in male Wistar rats, with several side actions, namely, reduced locomotion and neutralization of the antidepressant-like actions of desipramine.