Anorexia induced by M-trifluoromethylphenylpiperazine (TFMPP) in rats.

1-[3-(trifluoromethyl) phenyl] piperazine (TFMPP), a putative 5-HT1B, 5-HT1C and 5-HT2 agonist decreased dose-dependently food intake over 4 h in freely feeding rats. The TFMPP-induced anorexia was blocked by mesulergine (a 5-HT1C and 5-HT2 antagonist), metergoline (a 5-HT1A, 5-HT1B, 5-HT1C and 5-HT2 antagonist), mianserin (a 5-HT1C and 5-HT2 antagonist) and attenuated by ketanserin and ritanserin (5-HT2 antagonists). The examined anorexia was not antagonized by cyanopindolol and compound 21009 (5-HT1A and 5-HT1B antagonists). These results indicate that the TFMPP-induced anorexia in freely feeding rats is probably mediated by 5-HT2--and, may be also by 5-HT1C receptors.