The α-Bungarotoxin-binding Nicotinic Acetylcholine Receptor from Rat Brain Contains Only the α7 Subunit*
Abstract
When expressed in Xenopus oocytes, the rat α7 subunit forms homo-oligomeric nicotinic acetylcholine receptors, which are blocked by α-bungarotoxin. Since the pharmacological and physiological properties of the α7 receptor expressed in oocytes are similar to those of the α-bungarotoxin-sensitive nicotinic currents recorded from neuronal preparations and the distribution patterns of α7 mRNA and α-bungarotoxin-binding sites in the rat brain are very similar, α7 is thought to be the main component of the α-bungarotoxin-binding nicotinic receptor in the mammalian brain. However, while α7 is found in purified α-bungarotoxin-binding complexes from rat brain or PC12 cells, other proteins copurify with it. Therefore, the question whether α7 forms a homo-oligomeric α-bungarotoxin-binding nicotinic receptor in the mammalian brain remains. We have developed and characterized affinity-purified polyclonal antibodies and used these antibodies in Western blot analyses of α-bungarotoxin-binding proteins purified from rat brains. We report here that our experimental data support the current working hypothesis that the α-bungarotoxin-binding nicotinic receptor is a homo-oligomer of α7 subunits in the rat brain.
Footnotes
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↵* This work was supported in part by National Institutes of Health NINDS Grant NS13546 and National Institute on Drug Abuse Grant DA04077 (to J. W. P.).The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵‡ To whom correspondence should be addressed: Div. of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030. Tel.: 713-798-3100; Fax: 713-798-3946; E-mail: jpatrick{at}bcm.tmc.edu.
- Received May 23, 1997.
- Revision received July 8, 1997.
