MUSCARINIC ACETYLCHOLINE-RECEPTOR SUBTYPES IN THE HUMAN IRIS

Employing subtype-specific antisera, we measured the relative immunore activity of five muscarinic acetylcholine receptor (mAChR) subtype pro teins (m1-m5) in the human iris. The most intensive FITC immunofluores cence was detected by the anti-ms antibody, followed by anti-m1 and -m 5 antisera, in the iris sphincter muscle cells. Only very weak fluores cence was obtained by anti-IL and -m4 antibodies. In dilator muscle ce lls, weak but not consistent immunoreactivity was found by anti-mi and -m5 antibodies. The results suggest that the m3 muscarinic receptor i s the predominant subtype in sphincter muscle cells of the human iris. (C) 1998 Elsevier Science B.V.