Adrenergic activity of ortho-, meta-, and para-octopamine.
DL-o-, and p-octopamine were tested for beta- and alpha-adrenergic activity in rats. When compared to DL-isoproterenol, a beta-adrenergic agonist, all three isomers failed to show significant beta-adrenergic activity as assessed by intiation of thirst and by increase in tail skin temperature. All three isomers increased mean blood pressure in pentolinium-blocked rats. Of the three isomers, m-octopamine possessed the greatest alpha-adrenergic activity. When the responses were compared with those induced by L-norepinephrine, the order of activities was: 1:0.01 :0.0005 :0.0007 for norepinephrine, m-, p- and o-octopamine, respectively. Thus, DL-m-octopamine has about 1/100th the alpha-adrenergic activity of L-norepinephrine.
D000316:Adrenergic alpha-Agonists; D000318:Adrenergic beta-Agonists; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001831:Body Temperature / Q000187:drug effects; D004326:Drinking / Q000187:drug effects; D007536:Isomerism; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D009655:Octopamine / Q000494:pharmacology*; D051381:Rats; D011941:Receptors, Adrenergic / Q000187:drug effects*; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects*; D012881:Skin Temperature / Q000187:drug effects
D000316:Adrenergic alpha-Agonists; D000318:Adrenergic beta-Agonists; D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D009655:Octopamine; D007545:Isoproterenol; D009638:Norepinephrine