Format

Send to

Choose Destination
See comment in PubMed Commons below
J Physiol. 2003 Dec 15;553(Pt 3):857-71. Epub 2003 Oct 10.

Nicotine is highly effective at producing desensitization of rat alpha4beta2 neuronal nicotinic receptors.

Author information

1
Department of Anesthesiology, Washington University, St Louis, MO 63110, USA.

Abstract

We examined desensitization by acetylcholine (ACh) and nicotine at the rat alpha4beta2 neuronal nicotinic receptor stably expressed in HEK cells. For both agonists, the decay in response due to desensitization ('onset') was best fitted by the sum of two exponentials with the fast component dominant at concentrations > 1 microM. The time constants for onset were similar for both agonists, and showed little concentration dependence over the range of 0.1-100 microM. Recovery from desensitization also showed two exponential components. In contrast to the similarity in onset, nicotine produced longer lasting desensitization, resulting from an increase in the proportion of receptors in the slowly recovering population and from an increase in the time constant for the slow recovery process. The proportion of receptors in the slowly recovering population increased as the duration of the desensitizing pulse increased. Desensitization was also induced by low concentrations of agonist, with no apparent macroscopic response. A 100 s application of 10 nM nicotine desensitized 70 % of the peak response, while 100 s of 10 nM ACh desensitized only 15 %. At higher concentrations of agonist, which result in a macroscopic response, desensitization in the absence of activation also can occur. Nicotine is a very potent and efficacious desensitizing agent at this neuronal nicotinic receptor.

PMID:
14555718
PMCID:
PMC2343639
DOI:
10.1113/jphysiol.2003.053447
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Wiley Icon for PubMed Central
    Loading ...
    Support Center