Effects of surugatoxin on adrenergically innervated tissues

Effects of surugatoxin (SGTX), a new ganglionic blocking agent on adrenergically innervated tissues: guinea pig isolated atria and vas deferens were investigated. SGTX (1, 10 muM) markedly reduced the cardiostimulatory response of the atria to nicotine and also partially the response to 1,1-dimethyl-4-phenylpiperazinium (DMPP) and 5-hydroxytryptamine, without affecting responses to noradrenaline, tyramine and histamine. The contractile response of the vas deferens to nicotine, DMPP and hypogastric nerve stimulation was markedly reduced by SGTX (1, 10 muM), whereas that to noradrenaline, acetylcholine and transmural stimulation was not affected. These results indicate that SGTX has an antagonistic action on nicotinic receptors in these tissues as well as in sympathetic ganglia and in guinea pig ileum.