Excitatory effect of a new polypeptide (anthopleurin-B) from sea anemone on the guinea-pig vas deferens.
1 Anthopleurin-B (AP-B, greater than 3 x 10(-9) M), a newly isolated polypeptide from sea anemone (Anthopleura xanthogrammica), caused powerful rhythmic contractions in the guinea-pig isolated vas deferens. The other polypeptides anthopleurin-A from A. xanthogrammica and anthopleurin-C from A. elegantissima, elicited similar effects but in higher concentrations ( less than 5 x 10(-8) M). Toxin II (10(-6) M) isolated from the sea anemone, Anemonia sulcata, had no effect. 2 The rhythmic contractions induced by AP-B were inhibited by phentolamine, bretylium, guanethidine, reserpine, 6-hydroxydopamine, tetrodotoxin (TTX) and verapamil. Mecamylamine, atropine, methysergide, chlorpheniramine, and indomethacin had no effect. 3 AP-B (10(-8) M approximately 10(-5) M) caused a dose-dependent increase in the amount of endogenous noradrenaline (NA) released from the vas deferens. AP-B (10-5M) increased the amount of NA released to approximately 310 times (12 micrograms/g tissue) that of untreated tissues. 4 The AP-B-induced release of NA was inhibited or abolished by TTX, verapamil, or incubation in Ca-free medium. 5 These results suggest that the AP-B-induced rhythmic contraction of the vas deferens is mediated through the release of NA from adrenergic nerve endings; AP-B is one of the most potent substances in stimulating NA release from the vas deferens.
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism; D010455:Peptides / Q000494:pharmacology*; D013779:Tetrodotoxin / Q000494:pharmacology; D014649:Vas Deferens / Q000187:drug effects; D014700:Verapamil / Q000494:pharmacology
D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D013779:Tetrodotoxin; C026132:anthopleurin B; D014700:Verapamil; D002118:Calcium; D009638:Norepinephrine