Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Lobeline Attenuates the Locomotor-Activating Properties of Repeated Morphine Treatment in Rats

Dennis K Miller , James E Polston, Kelli R Rodvelt, Matthew J Will

Department of Psychological Sciences, Translational Neuroscience Center and Bond Life Sciences Center, University of Missouri, Columbia MO 65210, United States;

For correspondence:- Dennis Miller Email: millerden@missouri.edu Tel:+15738743502

Received: 14 December 2010 Accepted: 7 June 2011 Published: 20 August 2011

Citation: Miller DK, Polston JE, Rodvelt KR, Will MJ. Lobeline Attenuates the Locomotor-Activating Properties of Repeated Morphine Treatment in Rats. Trop J Pharm Res 2011; 10(4):421-429 doi: 10.4314/tjpr.v10i4.7

© 2011 The authors.
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Abstract

Purpose: Lobeline perturbs intra- and extracellular neurotransmitter levels and diminishes the in vitro and in vivo effects of psychostimulants. More recently, lobeline was shown to bind to µ opiate receptors, block the effects of opiate receptor agonists, and decrease heroin self-administration in rats. The present study determined the effect of lobeline on morphine-induced changes in locomotor behavior in rats.

Methods: For 12 consecutive days (Days 1 - 12), male rats were administered lobeline (0.3 or 1 mg/kg) followed by morphine (5 or 10 mg/kg) and locomotor activity was measured. On Day 13, the effect of lobeline on the expression of morphine-induced increases in activity was determined.

Results: With repeated morphine treatment, an increase in locomotor activity was observed. In a dose-dependent manner, lobeline decreased the morphine-induced increase in activity. Acute lobeline challenge on Day 13 also attenuated the expression of this morphine-induced increase in activity.

Conclusion: These results are consistent with previous work where lobeline blocks the locomotor-activtating properties of psychostimulants, and these findings support an emerging literature suggesting that lobeline produces its behavioral effects through an interaction with µ opiate receptors.

Keywords: Behavior, Morphine, Locomotor activity, Behavioural sensitization, Âµ Opiate receptors