Format

Send to

Choose Destination
See comment in PubMed Commons below
Neuropharmacology. 2001;40(2):178-84.

Effects of membrane cholesterol on the sensitivity of the GABA(A) receptor to GABA in acutely dissociated rat hippocampal neurones.

Author information

1
Department of Pharmacology, The School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX, UK.

Abstract

The effects of membrane cholesterol on the GABA(A) receptor were investigated in acutely dissociated rat hippocampal neurones, using the whole-cell patch clamp technique. Neuronal cholesterol was manipulated within the range 56-250% control by incubation with methyl-beta-cyclodextrin for depletion and a complex of cholesterol and methyl-beta-cyclodextrin for enrichment. Manipulation over a narrower range was achieved with cholesterol + phosphatidylcholine liposomes. A complex of epicholesterol and methyl-beta-cyclodextrin was used to insert epicholesterol. Cholesterol enrichment reduced the potency of GABA, as did cholesterol depletion, with increases in EC(50) of up to 4-fold. Cholesterol enrichment reduced the potency of the competitive antagonist bicuculline but did not affect that of the non-competitive antagonist picrotoxinin. Cholesterol depletion did not affect the potencies of either antagonist. Epicholesterol substituted functionally for cholesterol with respect to the effects of enrichment. In cholesterol-depleted neurones, however, only incubation with cholesterol was able to restore GABA potency to normal. These results suggest a specific requirement for cholesterol at control levels to maintain optimal GABA potency, which may involve specific binding of cholesterol to the GABA(A) receptor. The reduction in GABA potency by enrichment with cholesterol or epicholesterol is more likely to be due to reduced plasma membrane fluidity.

PMID:
11114396
[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Support Center