title: Evidence for purinergic innervation of the anococcygeus muscle.
abstract: 1 Fluorescence histochemical localization of quinacrine (which binds to adenosine 5'-triphosphate (ATP)) revealed nerve fibres running singly and in bundles in both rat and rabbit anococcygeus muscle. Single neurone cell bodies and ganglia containing between 2 and 50 cells were also observed.2 Catecholamine fluorescence studies revealed a dense adrenergic ground plexus, but no adrenergic ganglion cells were detected. No acetylcholinesterase-positive nerve fibres or ganglion cells were seen in the rat.3 When the tone was raised with guanethidine, a relaxation in response to field stimulation was revealed, which was unaffected by atropine but blocked by tetrodotoxin.4 Release of ATP increased 3 to 6 times above background during stimulation of these non-adrenergic, non-cholinergic, inhibitory nerves.5 Neither quinacrine staining nor the release of ATP during inhibitory nerve stimulation was affected by 6-hydroxydopamine treatment, which abolished catecholamine fluorescence.6 Exogenous ATP produced relaxation in high tone preparations of the rabbit anococcygeus muscle. ATP produced either contraction or a small relaxation followed by a contraction of the rat anococcygeus muscle, but treatment with low concentrations of the prostaglandin synthesis inhibitor indomethacin, converted the contraction to a relaxation.7 These data are consistent with the view that the anococcygeus muscle is innervated by purinergic inhibitory nerves.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001679:Biogenic Amines / Q000378:metabolism; D005260:Female; D006651:Histocytochemistry; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D008856:Microscopy, Fluorescence; D009130:Muscle, Smooth / Q000502:physiology; D011685:Purine Nucleotides / Q000502:physiology*; D011796:Quinacrine; D011817:Rabbits; D051381:Rats; D012007:Rectum / Q000294:innervation*
chemical_list: D001679:Biogenic Amines; D011685:Purine Nucleotides; D000255:Adenosine Triphosphate; D011796:Quinacrine; D007213:Indomethacin