Activities of octopamine and synephrine stereoisomers on octopaminergic receptor subtypes in locust skeletal muscle.
The activities of the (-) and (+)- forms of p-, m- and o-octopamine and p- and m-synephrine have been compared on the different subtypes of octopamine receptor present in the extensor-tibiae neuromuscular preparation from the locust hindleg. The rank order of potency of the (-)-forms on the OCTOPAMINE2A receptors was p-synephrine greater than p-octopamine greater than m-octopamine greater than o-octopamine greater than m-synephrine whilst the rank order of the (+)-forms was p-synephrine greater than p-octopamine greater than m-octopamine. (+)-m-Synephrine and (+)-o-octopamine had no effect on this class of receptor when tested up to a concentration of 10(-3) M. The rank order of potency of the (-)-forms on the OCTOPAMINE2B receptors was p-synephrine greater than p-octopamine greater than m-synephrine greater than m-octopamine greater than o-octopamine whilst the rank order of the (+)-forms was p-octopamine greater than p-synephrine greater than m-octopamine greater than o-octopamine. (+)-m-Synephrine again had no effect up to a concentration of 10(-3) M. The rank order of potency of the (-)-forms on the OCTOPAMINE1 receptors was p-synephrine greater than p-octopamine greater than m-synephrine greater than m-octopamine greater than o-octopamine, whilst the rank order of the (+)-forms was p-synephrine greater than p-octopamine greater than o-octopamine greater than m-synephrine greater than m-octopamine.(ABSTRACT TRUNCATED AT 250 WORDS)
Evans
P D
PD
Dept. of Zoology, University of Cambridge, UK.
Thonoor
C M
CM
Midgley
J M
JM
D000818:Animals; D005260:Female; D006110:Grasshoppers / Q000378:metabolism*; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000187:drug effects; D008297:Male; D009132:Muscles / Q000187:drug effects / Q000378:metabolism*; D009469:Neuromuscular Junction / Q000187:drug effects; D009655:Octopamine / Q000494:pharmacology*; D011941:Receptors, Adrenergic / Q000378:metabolism*; D017982:Receptors, Biogenic Amine; D013237:Stereoisomerism; D009435:Synaptic Transmission / Q000187:drug effects; D013578:Synephrine / Q000494:pharmacology*
D011941:Receptors, Adrenergic; D017982:Receptors, Biogenic Amine; C027604:norsynephrine receptor; D009655:Octopamine; C028435:2-octopamine; D013578:Synephrine