A single amino acid confers barbiturate sensitivity upon the GABA rho 1 receptor. |
| |
Authors: | D Belelli D Pau G Cabras J A Peters J J Lambert |
| |
Institution: | Department of Pharmacology and Neuroscience, Ninewells Hospital and Medical School, University of Dundee, Scotland. d.belelli@dundee.ac.uk |
| |
Abstract: | Many structurally diverse general anaesthetics enhance inhibitory neurotransmission in the central nervous system by interacting with the GABAA receptor. By contrast, GABA receptors composed of the rho 1 subunit are anaesthetic-insensitive. Here, we demonstrate that both delta-hexachlorocyclohexane (delta-HCH; 1-100 microM), a positive allosteric modulator of the GABAA receptor, and the anaesthetic pentobarbitone (10-600 microM) have no effect on GABA-evoked currents mediated by wild-type rho 1 recombinant receptors (expressed in Xenopus laevis oocytes). By contrast, these agents produce up to a 10 fold enhancement of GABA responses transduced by a rho 1 receptor in which a transmembrane located isoleucine residue is replaced by serine. However, not all general anaesthetics were similarly influenced by this mutation, because propofol and 5 beta-pregnan-3 alpha-ol-20-one (5 beta 3 alpha) remained ineffective. These data are discussed in relation to the specificity of general anaesthetic action. |
| |
Keywords: | |
|
|