A pharmacological analysis of serotonergic receptors: Effects of their activation of blockade in learning

Abstract

1. 1. The authors have tested several 5-HT selective agonists and antagonists (5-HT 1A/1B, 5-HT 1A/2B/2C, 5-HT 3 or 5-HT 4), an uptake inhibitor and 5-HT depletors in the autoshaping learning task. 2. 2. The present work deals with the receptors whose stimulation increases or decreases learning. 3. 3. Impaired consolidation of learning was observed after the presynaptic activation of 5-HT 1B, 5-HT 3 or 5-HT 4 or the blockade of postsynaptic 5-HT 2C/2B receptors. 4. 4. In contrast, an improvement occurred after the presynaptic activation of 5-HT 1A, 5-HT 2C, and the blockade of presynaptic 5-HT 2A, 5-HT 2C and 5-HT 3 receptors. 5. 5. The blockade of postsynaptic 5-HT 1A,5-HT 1B,5-HT 3 or 5-HT 4 receptors and 5-HT inhibition of synthesis and its depletion did no alter learning by themselves. 6. 6. The present data suggest that multiple pre- and postsynaptic serotonergic receptors are involved in the consolidation of learning 7. 7. Stimulation of most 5-HT receptors increases learning, however, some of 5-HT subtypes seem to limit the data storage. 8. 8. Furthermore, the role of 5-HT receptors in learning seem to require an interaction with glutamatergic, GABAergic and cholinergic neurotransmission systems.