Pharmacological and null mutation approaches reveal nicotinic receptor diversity

Citation
P. Whiteaker et al., Pharmacological and null mutation approaches reveal nicotinic receptor diversity, EUR J PHARM, 393(1-3), 2000, pp. 123-135
Citations number
24
Categorie Soggetti
Pharmacology & Toxicology
Journal title
EUROPEAN JOURNAL OF PHARMACOLOGY
ISSN journal
00142999 → ACNP
Volume
393
Issue
1-3
Year of publication
2000
Pages
123 - 135
Database
ISI
SICI code
0014-2999(20000330)393:1-3<123:PANMAR>2.0.ZU;2-V
Abstract
We have developed an array of assays for nicotinic acetylcholine receptor b inding and function. [I-125]alpha-Bungarotoxin-, (-)-[H-3]nicotine-, and [H -3]epibatidine-binding nicotinic acetylcholine receptors were assayed in mo use brain membranes and sections. Nicotinic acetylcholine receptor function was quantified using synaptosomal [H-3]dopamine, [H-3]gamma-aminobutyric a cid ([H-3]GABA), and Rb-86(+) efflux techniques. Additionally, the effects of beta 2 subunit deletion on each of the measures were assessed. Detailed pharmacological comparison revealed minimally six nicotinic binding subtype s: [I-125]alpha-bungarotoxin-binding nicotinic acetylcholine receptors; bet a 2-subunit-dependent and -independent high-affinity(-)-[H-3]nicotine-bindi ng sites; beta 2-dependent and -independent cytisine-resistant [H-3]epibati dine-binding sites; and a beta 2-dependent low-affinity [H-3]epibatidine bi nding site. Comparative pharmacology suggested that [H-3]GABA and dihydro-b eta-erythroidine (DH beta E)-sensitive Rb-86(+) efflux are mediated by the same (probably alpha 4 beta 2) nicotinic acetylcholine receptor subtype, wh ile other nicotinic acetylcholine receptor subtypes evoke [H-3]dopamine and DH beta E-resistant Rb-86(+) efflux. In whole-brain preparations, each mea sure of nicotinic acetylcholine receptor function was beta 2 dependent. The majority of beta 2-independent [H-3]epibatidine binding was located in sma ll, scattered brain nuclei, suggesting that individual nuclei may prove sui table for identification of novel, native nicotinic acetylcholine receptors . (C) 2000 Elsevier Science B.V. All rights reserved.