m-Octopamine: normal occurrence with p-octopamine in mammalian sympathetic nerves.
The development of a radiochemical enzyme assay for p-octopamine in 1969 led to its identification in a large number of invertebrate nerve systems and in mammalian sympathetic nerves. The original method by which p-octopamine was measured has now been found to be nonspecific; however, modifications of this procedure can determine both m- and p-octopamine. We recently developed a new specific method for the unequivocal identification and quantitative determination in tissue of the six octopamine and synephrine isomers. With this method--negative chemical ionization gas chromatography-mass spectrometry--the more physiologically active m-octopamine has been found in association with p-octopamine in 10 organs of the rat. m-Octopamine is present in concentrations equal to those of p-octopamine in heart, spleen, and liver and in concentrations from 30 to 60% of p-octopamine in adrenals, vas deferens, brain, kidney, large intestine, bladder, and lungs. In vivo inhibition of monoamine oxidase markedly increased the concentrations of both m- and p-octopamine in all organs examined. Both amines were virtually absent from all organs except the adrenals following chemical sympathectomy with 6-hydroxydopamine, thereby establishing that m- and p-octopamine are localized within sympathetic nerve endings.
D015078:2-Hydroxyphenethylamine / Q000031:analogs & derivatives / Q000032:analysis*; D000818:Animals; D008401:Gas Chromatography-Mass Spectrometry; D008297:Male; D008996:Monoamine Oxidase Inhibitors / Q000494:pharmacology; D009655:Octopamine / Q000032:analysis* / Q000031:analogs & derivatives; D010627:Phenethylamines / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains; D013564:Sympathetic Nervous System / Q000032:analysis*; D013578:Synephrine / Q000032:analysis
D008996:Monoamine Oxidase Inhibitors; D010627:Phenethylamines; D009655:Octopamine; D015078:2-Hydroxyphenethylamine; C028435:2-octopamine; C005310:norfenefrine; D013578:Synephrine