Imidazole has similar behavioural effects to yohimbine

A number of animal behavioural models were used to study the activity of imidazole (IMID) on the central nervous system. IMID antagonized in a dose-related fashion penile erections (PE) as well as stretching and yawning (SY) elicited in male rats by B-HT 920, an alpha 2 and dopamine (DA) autoreceptor agonist. Inhibition of B-HT 920-induced PE and SY was also exhibited by haloperidol, a DA receptor blocker, and yohimbine, but not by prazosin, alpha 2 and alpha 1 receptor antagonists respectively. Moreover IMID behaved similarly to yohimbine in: 1) counteracting clonidine-induced hypothermia in mice; 2) antagonizing sedation and sleep induced by clonidine and B-HT 920 in chicks, while haloperidol was ineffective. When administered to sexually active rats before the copulatory test, IMID at low doses, significantly altered some aspects of mating, a result which is interpretable in terms of enhanced sexual arousal and resembling the aphrodisiac effect reported for yohimbine. The neurochemical mechanisms involved in these effects are discussed.