Stimulation of 5-HT2A and 5-HT2C receptors blocks the reward-facilitating effect of cocaine in the rat

Abstract

Event Abstract Back to Event Stimulation of 5-HT2A and 5-HT2C receptors blocks the reward-facilitating effect of cocaine in the rat Vicky Katsidoni1* and George Panagis1 1 University of Crete, Greece Serotonin (5-HT) appears to play a modulatory role in the behavioral effects of cocaine, although the impact of specific 5-HT receptors in this control has not been fully established. In the present study, the efficacy of selective ligands for the 5-HT2A and 5-HT2C receptors in altering the reward-facilitating effect of cocaine was examined in rats. Male Sprague-Dawley rats were implanted with a monopolar stimulating electrode into the medial forebrain bundle at the level of the lateral hypothalamus. Rate-frequency functions were determined by logarithmically decreasing the number of cathodal pulses in a stimulation train from a value that sustained maximal responding to one that did not sustain responding. After brain reward threshold stabilized rats received systemic injections with the selective 5-HT2A agonist TCB-2 (0.3mg/kg), the selective 5-HT2A antagonist R-96544 (0.3mg/kg), the selective 5-HT2C agonist WAY-161503 (0.3mg/kg) and the selective 5-HT2C antagonist SB-242084 (0.5mg/kg), followed by acute administration of cocaine (5mg/kg). Systemic injections of the 5-HT2A and 5-HT2C agonists blocked the reward-facilitating effect of cocaine. These effects were reversed by pretreatment with selective 5-HT2A and 5-HT2C antagonists, respectively. Interestingly, the 5-HT2C antagonist appeared to act synergistically with cocaine increasing further its reward-facilitating effect. To the contrary, the 5-HT2A antagonist did not have an effect. The present data support the hypothesis that serotonin through 5-HT2A and 5-HT2C receptors exerts an inhibitory influence on the reward-facilitating effect of cocaine. Intracranial microinjections of these drugs into specific brain regions of the mesocorticolimbic dopaminergic system expressing high levels of 5-HT2A and 5-HT2C receptors could reveal the specific neuroanatomical substrate of the present actions. Supported by a grant from the Research Committee of the University of Crete (KA 2581) Conference: 41st European Brain and Behaviour Society Meeting, Rhodes Island, Greece, 13 Sep - 18 Sep, 2009. Presentation Type: Poster Presentation Topic: Poster presentations Citation: Katsidoni V and Panagis G (2009). Stimulation of 5-HT2A and 5-HT2C receptors blocks the reward-facilitating effect of cocaine in the rat. Conference Abstract: 41st European Brain and Behaviour Society Meeting. doi: 10.3389/conf.neuro.08.2009.09.187 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 10 Jun 2009; Published Online: 10 Jun 2009. * Correspondence: Vicky Katsidoni, University of Crete, Crete, Greece, panagis@uoc.gr Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Vicky Katsidoni George Panagis Google Vicky Katsidoni George Panagis Google Scholar Vicky Katsidoni George Panagis PubMed Vicky Katsidoni George Panagis Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.