Cognitive performance and cholinergic transmission: influence of muscarinic and nicotinic receptor blockade.
The cholinergic system is essential in mediating cognitive processes. Although there has been extensive research regarding cholinergic receptor subsystems, the specific contribution of the muscarinic and nicotinic receptor system to cognitive processes still has not been sufficiently explored. In the present study, we examined the selective contribution of muscarinic and nicotinic antagonism to cognitive performance in healthy human subjects. A single-blind, double-dummy, time-elapsed, repeated measures cross-over design was used on 15 healthy males. Subjects completed a neuropsychological test battery assessing a wide range of cognitive domains after 0.4 mg scopolamine (intravenous), 0.2 mg/kg mecamylamine (max. 15 mg; oral) or placebo. Subjects were tested under three conditions: placebo/placebo (PP), scopolamine/placebo (SP) and mecamylamine/placebo (MP). Results show that scopolamine significantly impaired the free recall and recognition performance in the verbal learning test. No other cognitive domain was affected, neither by scopolamine nor by mecamylamine. In line with the existing literature, antagonism of muscarinic receptors resulted in specific cognitive impairments, predominantly memory performance.
Voss
Bianca
B
Department of Psychiatry and Psychotherapy, RWTH Aachen University, Pauwelsstr. 30, Aachen 52074, Germany. bivoss@ukaachen.de
Thienel
Renate
R
Reske
Martina
M
Habel
Ute
U
Kircher
Tilo
T
D000328:Adult; D000704:Analysis of Variance; D003071:Cognition / Q000187:drug effects*; D018592:Cross-Over Studies; D006801:Humans; D008297:Male; D008464:Mecamylamine / Q000494:pharmacology*; D018727:Muscarinic Antagonists / Q000494:pharmacology*; D009483:Neuropsychological Tests; D018733:Nicotinic Antagonists / Q000494:pharmacology*; D012601:Scopolamine / Q000494:pharmacology*; D016037:Single-Blind Method; D013997:Time Factors; D055815:Young Adult
D018727:Muscarinic Antagonists; D018733:Nicotinic Antagonists; D008464:Mecamylamine; D012601:Scopolamine