Neuronal nicotinic acetylcholine receptors on bovine chromaffin cells: cloning, expression, and genomic organization of receptor subunits

J Neurochem. 1997 Feb;68(2):488-97. doi: 10.1046/j.1471-4159.1997.68020488.x.


Neuronal nicotinic acetylcholine receptors from bovine adrenomedullary chromaffin cells play a primary role in triggering catecholamine secretion. In the present study, their constituent subunits were characterized. In addition to the alpha 3 subunit, which we have previously cloned, the presence of alpha 5 and beta 4 but not of beta 2 subunits was detected by reverse transcription-PCR analysis of mRNA from adrenal medulla. In situ hybridization indicated that alpha 3, alpha 5, and beta 4 subunits are coexpressed in all chromaffin cells. The primary structure of alpha 5 and beta 4 subunits was determined and functional receptors were obtained upon coinjection of subunit cRNAs into Xenopus oocytes. In contrast to other beta 4-containing nicotinic receptors, the ones formed by the bovine beta 4 subunit are insensitive to the agonist cytisine. Finally, we characterized the intergenic region of alpha 3 and alpha 5 subunits, which together with the beta 4 subunit, form a gene cluster in rats and chickens. RNase assays and the existence of overlapping cDNAs indicate that, in the bovine genome, the alpha 3 and alpha 5 genes overlap at their 3' ends. This fact is probably due to inefficient transcription termination, as a result of weak polyadenylation signals.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Cattle
  • Chromaffin Cells / chemistry*
  • Cloning, Molecular
  • DNA, Complementary / genetics
  • Female
  • Gene Expression Regulation / physiology
  • Gene Library
  • Genome
  • Introns / genetics
  • Molecular Sequence Data
  • Neurons / chemistry
  • Oocytes / physiology
  • RNA, Messenger / analysis
  • Receptors, Nicotinic / chemistry
  • Receptors, Nicotinic / genetics*
  • Sequence Homology, Amino Acid
  • Transcription, Genetic / physiology
  • Xenopus


  • DNA, Complementary
  • RNA, Messenger
  • Receptors, Nicotinic