Immunological localization of m1-m5 muscarinic acetylcholine receptors in peripheral tissues and brain

Life Sci. 1993;52(5-6):441-8. doi: 10.1016/0024-3205(93)90300-r.


Knowledge of the distributions and functions of native m1-m5 muscarinic acetylcholine receptors in tissues is limited. To characterize the family of m1-m5 proteins directly, a panel of subtype-selective antibodies was generated against divergent i3 loop-fusion proteins. Each antibody was shown to bind a single cloned receptor specifically. In peripheral tissues and brain, four receptor proteins (m1-m4) were found to account for the vast majority of the muscarinic binding sites using immunoprecipitation studies with the subtype-specific antibodies. The subtypes were differentially distributed, although most tissues were comprised of a complex mixture of receptors. Moreover, within tissues there were major differences in the precise localization of the subtypes, as determined by immunocytochemistry. The immunological methods described offer a novel approach with exquisite sensitivity and specificity for delineating the distribution of m1-m5 receptors in animal and human tissues.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Animals
  • Brain / metabolism*
  • Humans
  • Ileum / metabolism
  • Immunohistochemistry
  • Lung / metabolism
  • Myocardium / metabolism
  • Receptors, Muscarinic / metabolism*
  • Salivary Glands / metabolism


  • Receptors, Muscarinic