Strathprints logo
Strathprints Home | Open Access | Browse | Search | User area | Copyright | Help | Library Home | SUPrimo

Nicotine self-administered directly into the VTA by rats is weakly reinforcing but has strong reinforcement enhancing properties

Farquhar, Morag and Latimer, Mary P and Winn, Philip (2012) Nicotine self-administered directly into the VTA by rats is weakly reinforcing but has strong reinforcement enhancing properties. Psychopharmacology, 220 (1). pp. 43-54. ISSN 0033-3158

Full text not available in this repository. (Request a copy from the Strathclyde author)

Abstract

Rats will lever press to deliver nanolitre quantities of nicotine or the muscarinic agonist carbachol directly into the ventral tegmental area (VTA). The purpose of these experiments was to investigate further the characteristics of nicotine self-administration directly into the VTA. This study aimed to confirm previous data relating to intra-VTA self-administration of nicotine and carbachol and then test two hypotheses: (a) that pre-sensitisation of nicotinic receptors is needed for robust intra-VTA self administration and (b) that rats will lever press for intra-VTA nicotine if pre-trained to associate lever pressing with a rewarding outcome. Rats were equipped with cannulae aimed at posterior VTA and allowed five sessions to self-administer nicotine or carbachol. In different experiments, rats were either pre-sensitised to nicotine by subcutaneous (s.c.) injections or pre-trained to lever press for food and a simultaneous conditioned stimulus light. We confirmed that carbachol had strong activating effects when self-administered into the VTA; selective responding for nicotine developed over five sessions by reduction in the amount of pressing on an inactive lever. Prior sensitisation did not improve responding for intra-VTA nicotine but training rats to lever press before putting them on the drug regime did potentiate pressing. The action of nicotine in the VTA might be better considered as reinforcement enhancing and that its intrinsic rewarding property here is at best weak. Identification of the VTA as a target for the reinforcement enhancing effects of nicotine is compatible with the reinforcement-related functions of VTA dopamine neurons and their cholinergic inputs.

Item type: Article
ID code: 33587
Keywords: acetylcholine, dopamine , intra-cranial self-administration , nicotine , pedunculopontine , reinforcement , reward , ventral tegmental area , Pharmacy and materia medica, Pharmacology
Subjects: Medicine > Pharmacy and materia medica
Department: Faculty of Science > Strathclyde Institute of Pharmacy and Biomedical Sciences
Related URLs:
    Depositing user: Pure Administrator
    Date Deposited: 22 Sep 2011 16:31
    Last modified: 05 Sep 2014 10:56
    URI: http://strathprints.strath.ac.uk/id/eprint/33587

    Actions (login required)

    View Item