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THE EFFECTS OF VASOACTIVE INTESTINAL POLYPEPTIDE AND OF ADENOSINE 5′‐TRIPHOSPHATE ON THE ISOLATED ANOCOCCYGEUS MUSCLE OF THE MOUSE
Author(s) -
GIBSON A.,
TUCKER J.F.
Publication year - 1982
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1982.tb09274.x
Subject(s) - vasoactive intestinal peptide , medicine , endocrinology , inhibitory postsynaptic potential , stimulation , apamin , taenia coli , adenosine , muscle relaxation , adenosine triphosphate , muscle contraction , biology , adrenergic , neuromuscular transmission , chemistry , contraction (grammar) , neuropeptide , potassium channel , receptor
1 Vasoactive intestinal polypeptide (VIP, 0.01–5 μ m ) produced dose‐related relaxations of the mouse anococcygeus muscle. 2 Following incubation with indomethacin (2.8 μ m 1 h) adenosine 5′‐triphosphate (ATP, 0.5–10 m m ) 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 μ m ) had no effect on the relaxation of mouse anococcygeus to field stimulation, VIP, or ATP. 5 2‐2′‐Pyridylisatogen tosylate (PIT, 50 μ m ) 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.