Localization of muscarinic receptors on peptide-containing neurones of the guinea pig myenteric plexus in tissue culture

Abstract

A combined autoradiographic and immunocytochemical procedure has been used to identify neurochemically the subpopulation of cultured myenteric neurones which expresses muscarinic receptors. Antibodies to substance P (SP), [Met]enkephalin (ENK), vasoactive intestinal polypeptide (VIP) and somatostatin (SOM) were used to immunostain cultures that had previously been labelled with the irreversible muscarinic antagonist. [ 3H]propylbenzilylcholine mustard. Most neurites which displayed SP-like, ENK-like or SOM-like immunoreactivity did not possess muscarinic receptors. In contrast, many VIP-like immunopositive fibres also possessed muscarinic receptors. The identity of the majority of neurones which express muscarinic receptors, that do not contain VIP, remains to be determined.