title: Mechanical stimulation of skeletal muscle generates lipid-related second messengers by phospholipase activation.
abstract: Repetitive mechanical stimulation of cultured avian skeletal muscle increases the synthesis of prostaglandins (PG) E2 and F2 alpha which regulate protein turnover rates and muscle cell growth. These stretch-induced PG increases are reduced in low extracellular calcium medium and by specific phospholipase inhibitors. Mechanical stimulation increases the breakdown rate of 3H-arachidonic acid labelled phospholipids, releasing free 3H-arachidonic acid, the rate-limiting precursor of PG synthesis. Mechanical stimulation also increases 3H-arachidonic acid labelled diacylglycerol formation and intracellular levels of inositol phosphates from myo-[2-3H]inositol labelled phospholipids. Phospholipase A2 (PLA2), phosphatidylinositol-specific phospholipase C (PLC), and phospholipase D (PLD) are all activated by stretch. The stretch-induced increases in PG production, 3H-arachidonic acid labelled phospholipid breakdown, and 3H-arachidonic acid labelled diacylglycerol formation occur independently of cellular electrical activity (tetrodotoxin insensitive) whereas the formation of inositol phosphates from myo-[2-3H]inositol labelled phospholipids is dependent on cellular electrical activity. These results indicate that mechanical stimulation increases the lipid-related second messengers arachidonic acid, diacylglycerol, and PG through activation of specific phospholipases such as PLA2 and PLD, but not by activation of phosphatidylinositol-specific PLC.
authors: Department of Pathology, Brown University, Providence, Rhode Island 02912.
authors: H H
authors: HH
authors: Vandenburgh
authors: J
authors: J
authors: Shansky
authors: P
authors: P
authors: Karlisch
authors: R L
authors: RL
authors: Solerssi
mesh_terms: D000818:Animals; D001717:Birds; D002478:Cells, Cultured; D004789:Enzyme Activation; D050356:Lipid Metabolism; D009132:Muscles / Q000166:cytology / Q000378:metabolism*; D010740:Phospholipases / Q000378:metabolism*; D010812:Physical Stimulation; D011453:Prostaglandins / Q000096:biosynthesis; D015290:Second Messenger Systems
chemical_list: D011453:Prostaglandins; D010740:Phospholipases