EMD386088 (5 mg/kg) has no effect on latent inhibition shown to both light and noise stimuli

Activation of 5-hydroxytyptamine(6) (5-HT(6)) receptors stimulates attentional switching and 5-HT(6) receptor antagonists are putative drugs for psychosis. Latent inhibition (LI) provides a pre-clinical model of attentional switching and ‘antipsychotic-like’ action and is known to be modulated by 5-hydroxytyptamine. In the present study, LI was shown in a fear conditioning procedure that measured suppression of drinking after conditioning with footshock. In two experiments (each n = 48) it was shown that pre-exposure to both light- and noise-conditioned stimuli reduced conditioned suppression relative to the corresponding non-pre-exposed control. However, counter to prediction, LI was intact after treatment with the 5-HT(6) agonist EMD386088 (5 mg/kg).