Immunohistochemical localisation of cholinergic muscarinic receptor subtype 1 (Mlr) in the guinea pig and human enteric nervous system

Abstract

Little is known regarding the location of cholinergic muscarinic receptor 1 (M1r) in the ENS, even though physiological data suggest that M1rs are central to cholinergic neurotransmission. This study localised M1rs in the ENS of the guinea pig ileum and human colon using fluorescence immunohistochemistry and RT-PCR in human colon. Double labelling using antibodies against neurochemical markers was used to identify neuron subytpes bearing M1r. M1r immunoreactivity (IR) was present on neurons in the myenteric and submucosal ganglia. The two antibodies gave similar M1r-IR patterns and M1r-IR was abolished upon antibody preabsorption. M1r-IR was present on cholinergic and nNOS-IR nerve cell bodi..