Further evidence for the functional role of nonsynaptic nicotinic acetylcholine receptors.
The function of nicotinic acetylcholine receptors in the main central systems has been documented in the past decade. These studies focused mostly on the synaptic functions, although acetylcholine is released dominantly into the extrasynaptic space and the majority of nicotinic acetylcholine receptors on remote neurons are found on extrasynaptic membranes. Here, we show further evidence for the role of nonsynaptic nicotinic functions in the cognitive and the reward system. Dendrites of gamma-amino-n-butyric acid (GABA)-containing interneurons of the hippocampus are densely equipped with nicotinic acetylcholine receptors. These cells play an important role in memory processing. We analysed the effects of nicotinic acetylcholine receptor stimulation on the Ca(2+) dynamics of interneurons in different dendritic compartments. We also investigated the role of nicotinic receptors in the nucleus accumbens where nicotine stimulated vesicular dopamine release via activation of receptors located on varicosities. Nicotine produced comparable effects with 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) on dopamine release. These examples demonstrate that nonsynaptic nicotinic acetylcholine receptors can effectively influence activity pattern of neural networks in key structures of central systems.
Sylvester Vizi
E
E
Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, P.O. Box 67, H-1450 Budapest, Hungary. esvizi@koki.hu
Rózsa
Balázs
B
Mayer
Aliz
A
Kiss
János P
JP
Zelles
Tibor
T
Lendvai
Balázs
B
D000818:Animals; D003712:Dendrites / Q000502:physiology; D004298:Dopamine / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D007395:Interneurons / Q000502:physiology; D008297:Male; D017551:Microdialysis; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000494:pharmacology; D009538:Nicotine / Q000008:administration & dosage / Q000494:pharmacology; D018722:Nicotinic Agonists / Q000494:pharmacology; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011978:Receptors, Nicotinic / Q000378:metabolism / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors
D018722:Nicotinic Agonists; D011978:Receptors, Nicotinic; D009538:Nicotine; D018817:N-Methyl-3,4-methylenedioxyamphetamine; D004298:Dopamine