Effect of adrenergic agonists on phosphoinositide breakdown in rat skeletal muscle preparations.
Adrenergic regulation of phosphoinositide breakdown in rat skeletal muscle was investigated in 30-min incubations with 10 mM LiCl. In rat hemidiaphragms, prelabelled with D-myo-[2-3H]inositol, addition of alpha-agonists (epinephrine, norepinephrine, phenylephrine) induced a 5-8-fold increase of [3H]inositol monophosphate accumulation. This could be prevented by inclusion of alpha-antagonists (phentolamine, prazosin). beta-Agonists and/or beta-antagonists had no effect. Similar experiments with isolated flexor digitorum brevis muscle fibers yielded confirmatory results. Functional integrity of beta-receptor mediated processes was suggested by the beta-agonist-induced increase of glucose 6-phosphate in hemidiaphragms and cAMP in fiber preparations. The results indicate that phosphoinositide breakdown in differentiated rat skeletal muscle is, at least in part, under alpha-adrenergic control.
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D002712:Chlorides / Q000494:pharmacology; D000242:Cyclic AMP / Q000096:biosynthesis; D005954:Glucosephosphate Dehydrogenase / Q000096:biosynthesis; D007295:Inositol Phosphates / Q000096:biosynthesis; D008094:Lithium / Q000494:pharmacology; D018021:Lithium Chloride; D008297:Male; D009132:Muscles / Q000187:drug effects* / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism*; D051381:Rats
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D000318:Adrenergic beta-Agonists; D002712:Chlorides; D007295:Inositol Phosphates; D010716:Phosphatidylinositols; D008094:Lithium; D000242:Cyclic AMP; D005954:Glucosephosphate Dehydrogenase; D018021:Lithium Chloride