Effects Of The Plant Alkaloid Tetrandrine On Human Nicotinic Acetylcholine Receptors

Department

neurobiology

Document Type

Article

Abstract

Functional effects of the well-characterized antagonist of L-type Ca2+ channels tetrandrine on recombinant human γ-aminobutyric acid type A (GABAA) (α1β2γ2s) receptor or human α7, α4β2, α1β1δγ and α1β1δε nicotinic acetylcholine receptors expressed in Xenopus oocytes were examined using two-electrode voltage clamp. Tetrandrine inhibited the function of acetylcholine nicotinic receptors, but it had no effect on GABAA receptors. Potency of inhibition was influenced by the receptor subtype and the rank order was α4β2>α7>α1β1δγ≅α 1β1δε. Functional inhibition of α4β2 and α1β1δγ receptors was noncompetitive, but only inhibition of α1β1δγ receptors was voltage-dependent. Binding of 125I-α-bungarotoxin to α1β1δγ or 3H-cytisine to α4β2 receptors was also inhibited by tetrandrine, but inhibition was noncompetitive and required concentrations higher than those needed to inhibit receptor function. Inhibition of both α7 receptor function and binding of 125I-α-bungarotoxin to α7 receptor were mixed competitive/noncompetitive and occurred at a similar concentration range. © 2002 Elsevier Science B.V. All rights reserved.

Publication Date

8-30-2002

Publication Title

European Journal of Pharmacology

ISSN

00142999

Volume

450

Issue

3

First Page

213

Last Page

221

Digital Object Identifier (DOI)

10.1016/S0014-2999(02)02155-6

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