The effect of methysergide and other receptor antagonists on fenfluramine-induced glucose uptake into the isolated rat hemidiaphragm.
Fenfluramine in therapeutic concentrations causes a significant and dose related increase in glucose uptake into isolated rat and human skeletal muscle in the presence of insulin. Using fenfluramine, 100 ng/ml, on the rat hemidiaphragm preparation the effects of the following receptor blocking drugs in concentrations up to 250 ng/ml were investigated on this phenomenon: atropine, haloperidol, mepyramine, methysergide, propranolol and thymoxamine. Only methysergide, the 5-HT antagonist, reduced the action of fenfluramine in relatively low concentrations of the drug which were dose related (10 ng/ml causing approximately 40% inhibition). This suggests that the peripheral as well as the central actions of fenfluramine are mediated through 5-HT receptors.
D000818:Animals; D003964:Diaphragm / Q000187:drug effects / Q000378:metabolism; D005260:Female; D005277:Fenfluramine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism*; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology; D008297:Male; D008784:Methysergide / Q000494:pharmacology*; D009132:Muscles / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000502:physiology*
D007328:Insulin; D011956:Receptors, Cell Surface; D005277:Fenfluramine; D005947:Glucose; D008784:Methysergide