Lobeline Attenuates
the Locomotor-Activating Properties of Repeated Morphine
Treatment in Rats
Dennis K Miller*, James E Polston, Kelli R Rodvelt
and 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:
E-mail: millerden@missouri.edu
Tel: +1-573-874-3502
Received: 14 December
2010. Revised
accepted: 7 June 2011
Tropical
Journal of Pharmaceutical Research, Aug 2011;
10(4): 421-429
http://dx.doi.org/10.4314/tjpr.v10i4.7
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, µ Opiate receptors.
