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Titolo:
Regulation of the activity of hippocampal stratum oriens interneurons by alpha 7 nicotinic acetylcholine receptors
Autore:
Buhler, AV; Dunwiddie, TV;
Indirizzi:
Dept Vet Affairs, Med Res Serv, Denver, CO USA Dept Vet Affairs Denver COUSA Vet Affairs, Med Res Serv, Denver, CO USA Univ Colorado, Hlth Sci Ctr, Neurosci Program, Denver, CO USA Univ Colorado Denver CO USA th Sci Ctr, Neurosci Program, Denver, CO USA Univ Colorado, Hlth Sci Ctr, Dept Pharmacol, Denver, CO 80262 USA Univ Colorado Denver CO USA 80262 r, Dept Pharmacol, Denver, CO 80262 USA
Titolo Testata:
NEUROSCIENCE
fascicolo: 1, volume: 106, anno: 2001,
pagine: 55 - 67
SICI:
0306-4522(2001)106:1<55:ROTAOH>2.0.ZU;2-N
Fonte:
ISI
Lingua:
ENG
Soggetto:
RAT HIPPOCAMPUS; ALZHEIMERS-DISEASE; CHOLINERGIC INNERVATION; GABAERGIC INTERNEURONS; SYNAPTIC TRANSMISSION; CA1 INTERNEURONS; SEPTAL NEURONS; THETA-RHYTHM; DESENSITIZATION; ACTIVATION;
Keywords:
alpha-bungarotoxin; GABA; acetylcholinesterase; theta rhythm; desensitization; synaptic;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
50
Recensione:
Indirizzi per estratti:
Indirizzo: Buhler, AV Univ Iowa, Dept Pharmacol, BSB Rm 2-351, Iowa City, IA 52242 USA Univ Iowa BSB Rm 2-351 Iowa City IA USA 52242 ity, IA 52242 USA
Citazione:
A.V. Buhler e T.V. Dunwiddie, "Regulation of the activity of hippocampal stratum oriens interneurons by alpha 7 nicotinic acetylcholine receptors", NEUROSCIENC, 106(1), 2001, pp. 55-67

Abstract

GABAergic interneurons have been shown to be a major target of cholinergicinputs to the hippocampus. Because these interneurons project to pyramidalneurons as well as other interneurons, activation of the cholinergic system is likely to produce a complex modulation of local inhibitory activity. To better understand the role of postsynaptic alpha7 nicotinic acetylcholinereceptors in the hippocampus, we have characterized the effects of nicotinic agents on local interneurons of the rat CAI stratum oriens in terms of activation, desensitization, and region of axonal termination. Fast application of acetylcholine onto stratum oriens interneurons during whole-cell recordings from hippocampal slices activated the majority of cells tested, andthese responses were mediated almost entirely by alpha7 nicotinic acetylcholine receptors. Anatomical reconstructions showed no clear relationship between the acetylcholine responsivity of interneurons and the regions to which their axons project. Currents mediated by a7 receptors declined markedlyduring repetitive activation in the theta rhythm range (4-12 Hz) when activated by either pressure application or synaptic release of acetylcholine. However, the decay of alpha7 receptor-mediated currents was unaffected by treatment with the cholinesterase, inhibitor neostigmine (10 nM-10 muM), suggesting that hydrolysis of acetylcholine is not a rate-limiting step in thetermination of these responses. From these findings we suggest that nicotinic receptor activity in this region has an extensive and complex impact on local inhibitory circuits that is mediated by activation of several classes of intrinsic GABAergic cells. In addition, desensitization of the a7 nicotinic acetylcholine receptor is likely to contribute to the decay of individual responses to pressure application of agonist, and may also act in a cumulative fashion to impair the ability of these receptors to support repetitive activity during trains of activation. If applicable to alpha7 receptor responses in vivo, we suggest it may be difficult to enhance these responses for therapeutic purposes withcholinesterase inhibitors. (C) 2001 IBRO. Published by Elsevier Science Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/01/20 alle ore 16:06:08