ALAEI H, HUOTARI M, PIEPPONEN P, AHTEE L, HANNINEN O, MANNISTO P. MORPHINE RELE ASES GLUTAMATE THROUGH AMPA RECEPTORS IN THE VENTRAL TEGMENTAL AREA: A MICRODIALYSIS STUDY IN CONSCIOUS RATS. Med J Islam Repub Iran 2003; 17 (3) :225-231
URL:
http://mjiri.iums.ac.ir/article-1-686-en.html
From theDepartment of Physiology, University of Esfahan, Iran, theDepartment of Pharmacology and Toxicology, University of Kuopio, Finland , alaei@med.mui.ac.ir
Abstract: (4550 Views)
In vivo microdialysis was used to study the effects of morphine on glutamate
release from the ventral tegmentum area (VTA) in freely moving rats. Intraperitoneal
(i.p.) injection of acute and repeated morphine at increasing doses significantly
enhanced glutamate release. Only a minor tolerance developed to this dosage
of morphine. AP-S (2-amino-5-phosphonovaleric acid, 0.5 mg/kg i.p.), a
NMDA receptor antagonist, given 20 min before each repeated morphine injection,
did not have a significant effect on the stimulated glutamate release . Conversely,
injection of CNQX (6-cyano-7-nitroquinoxaline-2, 3-dione, 0.5 mg/kg
i.p.), an AMPA receptor antagonist, 20 min before each morphine dose was found
to markedly inhibit morphine-induced glutamate release in the VTA. In all experiments,
glutamate release reduced by time. These results show for the first
time that acute and repeated injection of morphine stimulates glutamate release in
the conscious rat VTA via AMPA receptors.