The effects of vasoactive intestinal polypeptide and of adenosine 5'-triphosphate on the isolated anococcygeus muscle of the mouse.
1 Vasoactive intestinal polypeptide (VIP, 0.01- MicroM) produced dose-related relaxations of the mouse anococcygeus muscle. 2 Following incubation with indomethacin (2.8 microM 1 h) adenosine 5'-triphosphate (ATP, 0.5-10 mM) produced dose-related relaxations of the mouse anococcygeus. 3 Haemolysed blood reduced inhibitory responses of the mouse anococcygeus to field stimulation but had no effect on relaxations to VIP or ATP. 4 Apamin (0.5 microM) had no effect on the relaxation of mouse anococcygeus to field stimulation, VIP, or ATP. 5 2-2'-Pyridylisatogen tosylate (PIT, 50 microM) itself reduced muscle tone but it did not abolish inhibitory responses to field stimulation, VIP, or ATP. 6 During prolonged inhibitory nerve stimulation the relaxation of the mouse anococcygeus in response to VIP was reduced greatly while that to ATP was unaffected. 7 Bundles of VIP-immunoreactive sites were detected in sections of the mouse anococcygeus treated by the peroxidase-antiperoxidase (PAP) immunocytochemical technique. 8 The results suggest that the mechanisms underlying non-adrenergic, non-cholinergic inhibitory transmission in the mouse anococcygeus are similar to those in the bovine retractor penis and unlike those in the guinea-pig taenia caeci. 9 The possibility that VIP or ATP might be involved in inhibitory neurotransmission in the mouse anococcygeus is discussed.
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D001030:Apamin / Q000494:pharmacology; D001790:Blood Physiological Phenomena; D004558:Electric Stimulation; D005768:Gastrointestinal Hormones / Q000494:pharmacology*; D006461:Hemolysis / Q000187:drug effects; D066298:In Vitro Techniques; D007510:Isatin / Q000031:analogs & derivatives / Q000494:pharmacology; D008297:Male; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects*; D009126:Muscle Relaxation / Q000187:drug effects*; D011863:Radioimmunoassay; D014660:Vasoactive Intestinal Peptide / Q000032:analysis / Q000494:pharmacology*
D005768:Gastrointestinal Hormones; D001030:Apamin; D014660:Vasoactive Intestinal Peptide; C009128:2,2'-pyridylisatogen tosylate; D007510:Isatin; D000255:Adenosine Triphosphate