title: Stimulation by octopamine of the sodium efflux in barnacle muscle fibres.
abstract: The behaviour of the ouabain-insensitive Na efflux in barnacle muscle fibres towards DL-octopamine has been investigated. It is found that these fibres are quite often sensitive to external application of octopamine. A concentration as low as 10(-9) M is effective. The kinetic results indicate that the stimulatory response develops within 5-10 min of exposure of the fibre to octopamine and is transitory in nature. The response to octopamine is greater in size in the presence of 1-isoamyl-3-isobutylxanthine (IAX) than in the presence of 1-propyl-3-methyl-7-(5-hydroxyhexyl)-xanthine (PMX). But neither IAX nor PMX stops the response from decaying. The response to octopamine is highly dependent on the presence of external Ca2+. The provisional conclusion is that the barnacle muscle fibre may be a useful preparation for studying the hormonal function of octopamine.
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002742:Chlorphenamidine / Q000031:analogs & derivatives / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D009132:Muscles / Q000187:drug effects / Q000378:metabolism*; D009655:Octopamine / Q000494:pharmacology*; D010042:Ouabain / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism*; D013806:Theophylline / Q000031:analogs & derivatives / Q000494:pharmacology; D001468:Thoracica / Q000378:metabolism*
chemical_list: D009655:Octopamine; C011741:demethylchlordimeform; C020955:1-propyl-3-methyl-7-(5-hydroxyhexyl)xanthine; D010042:Ouabain; C024045:1-isoamyl-3-isobutylxanthine; D012964:Sodium; D013806:Theophylline; D002742:Chlorphenamidine; D002118:Calcium; D015056:1-Methyl-3-isobutylxanthine