Neuronal nicotinic acetylcholine receptors expressed inXenopusoocytes: role of the α subunit in agonist sensitivity and desensitization

✍ Scribed by Adrian Gross; Marc Ballivet; Duri Rungger; Daniel Bertrand

• Publisher: Springer
• Year: 1991
• Tongue: English
• Weight: 825 KB
• Volume: 419
• Category: Article
• ISSN: 0031-6768
• DOI: 10.1007/bf00370805

✦ Synopsis

Neuronal nicotinic acetylcholine receptors (nAChRs) were expressed in J(enopus laevis oocytes after nuclear injection of complementary deoxyribonucleic acid (eDNA) expression vectors. The two receptor subtypes e4/nc~l and e3/nel were readily distinguishable from one another by ACh sensitivity and desensitization. c~3/ncO receptors showed lower ACh sensitivity and stronger desensitization than e4/ncO receptors. Furthermore, although the current/voltage relationship was very similar in both receptor subtypes, the voltage dependence of desensitization was found to be strikingly different. As the nel subunit was unchanged, the e subunits must be responsible for these functional differences. Symmetric hybrid ~ cDNAs, c~4: c~3 and ~3 : c~4, were constructed and functional receptors were obtained by co-injection with ned. These hybrid receptors displayed an ACh sensitivity that was mainly defined by the extracellular sequence of the c~ subunit. In contrast, no part of the ~ subunit was found fully to determine desensitization.