The effect of repeated treatment with antidepressant drugs on the thyrotropin-releasing hormone (TRH)-induced hyperthermia in mice.

The effect of acute (single dose) or repeated (twice daily, for 14 days) administration of 10 mg kg-1 p.o. of imipramine, amitriptyline, citalopram or mianserin has been examined on the hyperthermia induced by thyrotropin-releasing hormone (TRH) (40 mg kg-1 i.p., 2, or 2 and 72 h after single or last dose of antidepressants, respectively) in mice. Both imipramine and amitriptyline, given repeatedly, potentiated the TRH response, though the effect was observed 2 but not 72 h after the last dose of those drugs. Potentiation was also found after the single dose of imipramine or amitriptyline. On the other hand, citalopram and mianserin, administered either acutely or repeatedly, did not affect the TRH-induced hyperthermia.