Scopolamine induces up-regulation of nicotinic receptors in intact brain but not in nucleus basalis lesioned rats.
The effect of chronic scopolamine treatment on muscarinic and nicotinic receptors in frontoparietal cortex in rats was investigated. Administration of the muscarinic antagonist, scopolamine (10 mg/kg i.p./day) for 21 days, produced a significant increase in the density of both muscarinic and nicotinic receptors by 27.7% and 12.1% respectively as measured by the specific binding of (-)-[3H]quinuclidinylbenzilate and (-)-[3H]-nicotine. There was no modification in the affinities for these ligands. Rats, bilaterally lesioned with ibotenic acid at the level of nucleus basalis of Meynert, which innervates the frontoparietal cortex, showed no up-regulation of cortical nicotinic receptors after chronic scopolamine treatment, suggesting the importance of the synaptic integrity in the regulation mechanism.
Vige
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Department of Biochemical Pharmacology, Centre de Recherche Pierre Fabre, Castres, France.
Briley
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M
D000818:Animals; D001479:Basal Ganglia / Q000378:metabolism*; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D007051:Ibotenic Acid; D008297:Male; D009434:Neural Pathways / Q000187:drug effects / Q000378:metabolism; D009538:Nicotine / Q000378:metabolism; D011813:Quinuclidinyl Benzilate / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism; D011978:Receptors, Nicotinic / Q000187:drug effects / Q000378:metabolism*; D012601:Scopolamine / Q000494:pharmacology*; D013377:Substantia Innominata / Q000187:drug effects / Q000378:metabolism*
D011976:Receptors, Muscarinic; D011978:Receptors, Nicotinic; D007051:Ibotenic Acid; D011813:Quinuclidinyl Benzilate; D009538:Nicotine; D012601:Scopolamine