The localization of vasoactive intestinal polypeptide (VIP) in the anococcygeus muscle of the rat, rabbit and cat was investigated by radioimmunoassay and immunohistochemistry. High concentrations of VIP-like immunoreactivity were found in the anococcygeus muscle of all 3 species. VIP-like immunoreactivity was observed in a network of nerve fibres branching throughout the muscle which were unaffected by treatment with 6-hydroxydopamine. VIP, when applied exogenously to isolated preparations of the anococcygeus, produced dose-related relaxations of tone in all 3 species with a time course and maximum response similar to non-adrenergic, non-cholinergic inhibitory nerve stimulation. These observations provide further evidence in support of VIP as a suitable candidate for the non-adrenergic, non-cholinergic inhibitory neurotransmitter in the anococcygeus muscle.
- anococcygeus muscle
- non-adrenergic, non-cholinergic inhibitory nerves
- vasoactive intestinal polypeptide
ASJC Scopus subject areas
- Molecular Biology
- Clinical Neurology
- Developmental Biology