Influence of gonadotropin-releasing hormone on castration-induced 'depression' in mice: a behavioral and binding study.
Long-term (33-35 days) castration caused a significant increase in the duration of immobility of male and female mice in the tail suspension test (an animal model of depression), and a significant decrease in the maximum number (Bmax) of [3H]imipramine binding sites in the cerebral cortex of male mice. In the tail suspension test, gonadotropin-releasing hormone (GnRH), s.c. injected 3 times at 3-h intervals at doses of 0.2, 2 or 20 micrograms/kg, did not significantly modify the duration of immobility of castrated animals and did not reduce that of sham-operated ones, while desipramine (20 mg/kg s.c. 1 h before testing) restored immobility to normal in castrated animals and reduced it significantly in sham-operated ones. The same treatment schedule with GnRH produced an increase in the number of [3H]imipramine Bmax in cortical membranes that was statistically significant at the dose of 2 micrograms/kg. It is concluded that the castration-induced depression-like behavior in mice seems not to be due to the decreased levels and release of GnRH, and that GnRH has no antidepressant-like effect in mice, at least at our dose levels; however, GnRH seems to increase the number of cortical [3H]imipramine binding sites.
Bernardi
M
M
Institute of Pharmacology, University of Modena, Italy.
Sandrini
M
M
Vergoni
A V
AV
Marrama
D
D
Tagliavini
S
S
Bertolini
A
A
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D002352:Carrier Proteins; D002369:Castration; D002540:Cerebral Cortex / Q000378:metabolism; D003863:Depression / Q000523:psychology*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism / Q000494:pharmacology*; D007099:Imipramine / Q000378:metabolism; D008297:Male; D051379:Mice; D009919:Orchiectomy; D010052:Ovariectomy; D011955:Receptors, Drug; D017981:Receptors, Neurotransmitter / Q000378:metabolism
D002352:Carrier Proteins; D011955:Receptors, Drug; D017981:Receptors, Neurotransmitter; C027775:imipramine receptor; D007987:Gonadotropin-Releasing Hormone; D007099:Imipramine