Involvement of the serotonergic type 1A (5-HT1A) receptor in the agranularinsular cortex in the consolidation of memory for inhibitory avoidance in rats

Adult male Wistar rats were bilaterally implanted with indwelling cannulae in the agranular insular cortex of the prefrontal cortex. After recovery, a nimals were trained in a step-down inhibitory avoidance task (3.0-s, 0.4-mA footshock) and received, immediately after training, a 0.5-mul infusion of the serotonergic type 1A (5-HT1A) receptor agonist dipropylamino-8-hydroxy -1,2,3,4-tetrahydronaphthalene hydrobromide (8-OH-DPAT) or of the 5-HT1A re ceptor antagonist 1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl] piperazine hydrobromide (NAN-190), or of vehicle alone (20% DMSO). Retention testing was carried out 24 h after training. 8-OH-DPAT (1.25 and 6.25 mug but not 0 .0125 or 0.125 mug) was amnesic. NAN-190 was not effective at 0.125 or 1.25 mug any dose but reversed amnesia when given at 1.250 mug simultaneously w ith both effective doses of 8-OH-DPAT. These results show that an overactiv ation of 5-HT1A receptors in the agranular insular cortex impairs memory co nsolidation of inhibitory avoidance, in rats, immediately after training. T his suggests that these receptors of the insular cortex may modulate memory consolidation. (C) 2001 Lippincott Williams & Wilkins.