Journal
PHARMACOLOGY BIOCHEMISTRY AND BEHAVIOR
Volume 81, Issue 3, Pages 657-663Publisher
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.pbb.2005.05.006
Keywords
benzodiazepine; opioid; GABA; diazepam; naltrexone; naloxone; taste; food intake; reward; hedonic; palatability; parabrachial nucleus; nucleus accumbens; mesolimbic; brainstem; limbic system; anxiolytic
Funding
- NIDA NIH HHS [DA015188] Funding Source: Medline
- NIMH NIH HHS [MH63649] Funding Source: Medline
Ask authors/readers for more resources
Opioid agonists and benzodiazepine agonists each increase food intake. Both also increase hedonic 'liking' reactions to sweet tastes in rats. Do opioids and benzodiazepines share overlapping mechanisms of hedonic impact? Or are benzodiazepine and opioid effects on hedonic impact mediated by independent mechanisms? The present study examined whether blockade of opioid receptors prevents benzodiazepine-induced enhancement of taste palatability, as assessed by the affective taste reactivity test. Rats were implanted with oral cannulae, and prior to an oral infusion of bittersweet quinine-sucrose solution, all received i.p. injections of either vehicle, or diazepam alone (5 mg/kg diazepam + 0 mg/kg naltrexone), naltrexone alone (1 mg/kg naltrexone + 0 mg diazepam), or both diazepam plus naltrexone (5 mg/kg diazepam + 1 mg/kg naltrexone). Videotaped hedonic ('liking') and aversive ('disliking') orofacial reactions elicited by sucrose/quinine taste were compared across drug conditions. Diazepam administration alone more than doubled hedonic 'liking' reactions to the bittersweet taste, while reducing 'disliking' in half, compared to vehicle levels. Naltrexone by itself had little effect on taste-elicited affective reactions, and only marginally increased aversive gapes. However, naltrexone completely blocked diazepam's enhancement of positive hedonic 'liking' reactions, and naltrexone similarly disrupted diazepam-reduction of aversive 'disliking' taste reactions. These results indicate that endogenous opioid neurotransmission may be crucial to benzodiazepine enhancement of hedonic 'liking' for natural taste reward. (c) 2005 Elsevier Inc. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available