Journal article
Channel gating in the absence of agonist by a homooligomeric molluscan GABA receptor expressed in Xenopus oocytes from a cloned cDNA
Invertebrate Neuroscience, Vol.1(3), pp.267-272
1995
Abstract
We have previously described the isolation of a complementary DNA (cDNA) from the freshwater mollusc Lymnaea stagnalis encoding a polypeptide that exhibits ∼50% identity to the ß-subunits of vertebrate γ-aminobutyric acid (GABA) type A (GABAA) receptor. When expressed in Xenopus laevis oocytes from in vitro-transcribed RNA, the snail subunit forms functional homo-oligomeric receptors possessing chloride-selective ion channels. In recordings from voltage-clamped oocytes held at -60 mV, GABA induced an inward current, whereas application of the chloride-channel blocker picrotoxin (in the absence of agonist) elicited an apparent outward current. Single channel recordings obtained from cell-attached patches have revealed a single population of ∼20 pS channels, with an open probability greater than 90% (at a pipette potential of -100 mV) in the absence of GABA. The relationship between single channel current and pipette potential was linear over the studied range (-100 mV to +60 mV), but the open probability was less for hyperpolarizations than for depolarizations. The spontaneous channel openings were blocked by micromolar concentrations of picrotoxin. Functional hetero-oligomeric receptors were formed when the molluscan subunit was co-expressed in oocytes with the bovine GABAA receptor α1-subunit, but the channels gated by these receptors did not open spontaneously. © 1995 Sheffield Academic Press.
Details
- Title
- Channel gating in the absence of agonist by a homooligomeric molluscan GABA receptor expressed in Xenopus oocytes from a cloned cDNA
- Authors
- N S Bhandal (Author) - University of Nottingham, United KingdomR L Ramsey (Author) - University of Nottingham, United KingdomRobert J Harvey (Author) - Universität Hamburg, GermanyM G Darlison (Author) - Universität Hamburg, GermanyP N R Usherwood (Author) - University of Nottingham, United Kingdom
- Publication details
- Invertebrate Neuroscience, Vol.1(3), pp.267-272
- Publisher
- Springer
- DOI
- 10.1007/BF02211028
- ISSN
- 1354-2516
- Organisation Unit
- Centre for Bioinnovation; School of Health and Behavioural Sciences - Legacy; School of Health and Sport Sciences - Legacy; University of the Sunshine Coast, Queensland; School of Health
- Language
- English
- Record Identifier
- 99450543502621
- Output Type
- Journal article