Nicotine self-administration acutely activates brain reward systems and induces a long-lasting increase in reward sensitivity
by
Kenny PJ, Markou A.
Department of Neuropharmacology,
The Scripps Research Institute,
La Jolla, CA 92037, USA.
Neuropsychopharmacology. 2006 Jun;31(6):1203-11.


ABSTRACT

Nicotine is a major component of tobacco smoke contributing to the initiation and persistence of the harmful tobacco habit in human smokers. The reinforcing effects of nicotine likely arise through its ability to stimulate brain circuitry mediating the detection and experiencing of natural rewards. Nevertheless, remarkably little is known concerning the acute or long-lasting actions of nicotine on brain reward systems in vivo. Here, we investigated the effects of intravenously self-administered nicotine (0.03 mg/kg/infusion, free base) on the sensitivity of brain reward systems, reflected in alterations of intracranial self-stimulation (ICSS) thresholds in rats. Rats self-administered nicotine during 1 or 12 h daily sessions, with reward thresholds assessed 1 h before and 15 min after each self-administration session. Control rats remained nicotine naive throughout. Nicotine self-administration increased the sensitivity of brain reward systems, detected by post-nicotine lowering of reward thresholds in 1 and 12 h rats. This nicotine-enhanced sensitivity of reward systems was reversed by the high-affinity nicotinic receptor antagonist dihydro-beta-erythroidine (DHbetaE; 3 mg/kg). Surprisingly, nicotine-induced excitation of reward systems persisted for at least 36 days after nicotine self-administration had ceased. Overall, these data demonstrate that rats can voluntarily consume quantities of nicotine sufficient to increase the sensitivity of brain reward systems, an action likely crucial in establishing and maintaining the nicotine habit. Moreover, self-administered nicotine resets the sensitivity of reward systems to a new increased level, thereby imprinting an indelible 'memory' of its effects in reward systems, an action that so far appears unique to nicotine among drugs of abuse.
Nicotine withdrawal
Free-base nicotine
Nicotine : structure
Parkinson's disease
Smoking and MAO-A
Smoking and MAO-B
Nicotine neuroprotection
Cigars, bidis, and kreteks
Nicotine, dopamine and reward
Muscarinic + nicotinic receptors
Bupropion and nicotinic receptors
Bupropion (Zyban) for cigarette smokers
Quitting smoking: the role of antidepressants


Refs
and further reading

HOME
HedWeb
Nootropics
erythroxylum-coca.com
Future Opioids
BLTC Research
MDMA/Ecstasy
Superhapiness?
Utopian Surgery?
The Abolitionist Project
The Hedonistic Imperative
The Reproductive Revolution
Critique of Huxley's Brave New World

The Good Drug Guide
The Good Drug Guide

The Responsible Parent's Guide
To Healthy Mood Boosters For All The Family