Title

Characterization Of Human α4β2 Neuronal Nicotinic Receptors Stably Expressed In Sh-Ep1 Cells

Department

neurobiology

Document Type

Article

Abstract

These studies characterized human α4β2 neuronal nicotinic receptors stably expressed in a human epithelial cell line (SH-EP1). Receptors in transfected SH-EP1-hα4β2 cells were functional, as determined by increases in intracellular Ca2+in response to a nicotine stimulus. Nicotine increased Fura-2 fluorescence in a concentration-dependent manner with an apparent EC50 of 2.4 μM, a response that was blocked by the specific antagonist mecamylamine. When cells were incubated in 50 nM nicotine for 24 hours, the Ca2+ response inactivated by 44%, an effect that recovered within 24 hours. SH-EP1-hα4β2 cells expressed a single class of high affinity binding sites for [3H]cytisine with a Kd of 0.63 ± 0.08 nM and a Bmax of 6797 ± 732 femtomoles/mg protein. Incubation of cells with 50 nM nicotine for 24 hours increased the Bmax by 45% without changing affinity, a concentration-dependent effect with an EC50 of 58.6 nM. The nicotine-induced up regulation was reversible, and control values were achieved within 24 hours. Results indicate that SH-EP1-hα4β2 cells may be a good model system to study regulation of human α4β2 receptors, the most abundant nicotinic receptor subtype in brain.

Publication Date

8-29-2001

Publication Title

Neurochemical Research

ISSN

03643190

Volume

26

Issue

6

First Page

683

Last Page

693

Digital Object Identifier (DOI)

10.1023/A:1010995521851

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