Neither a high dose of the selective serotonin reuptake inhibitor citalopram (100 mu mol kg(-1) s.c.), nor the 5-HT1A receptor antagonist N-[2-[4-(2-methoxyphenyl)-1-piperaziny]-N-ethyl]-N-(2-pyridinyl) cyclohexane carboxamide 3HCl (WAY 100635) (0.1-0.4 mu mol kg(-1) s.c.) produced any evidence of catalepsy in adult male rats. When combined with citalopram, however. WAY 100635 produced a dose-dependent, and statistically significant, catalepsy in the inclined grid test. (C) 2001 Elsevier Science B.V. All rights reserved.