Erowid References Database
“The physiology and pharmacology of the anococcygeus muscle”.
Trends in Pharmacological Sciences. 1980;1(16):453-457.
When the rat anococcygeus was first introduced as a preparation for pharmacolocical studies some ten years ago it was suggested that it should prove ‘useful both for teaching and research’. How far has this proved to be true? The first preparation was the in vitro rat anococcygeus muscle. Since then the range has been extended to include an in vivo examination in the rat and in vitro (MISSING WORD) on the bovine anococcygeus muscle. All have in common a motor adrenergic innervation and inhibitory nerves whose transmitter remains unknown. While their innervation is similar, the properties of the muscle fibres themselves differ widely from the rat anococcygeus with no spontaneous tone and few receptor types through the dog muscle which is also atonic but now (MISSING TEXT)....... tone, H1 motor receptors and now beta-adrenoreceptors, muscarine receptors and weak H2-histamine receptors all mediating relaxation (Table I). Table I also illustrates the difficulty in suggesting a likely inhibitory transmitter from agonist action. On the assumption that it will be the same in all species, candidates such as acetylcholine, dopamine, histamine, 5-HT, GABA and glycine can be excluded since in the ratthey are either ineffective or mediate contraction. Two possibilities are a peptide or ATP. Normally ATP has little effect other than a weak contraction at high concentrations. In the presence of indometacin to inhibit
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