Possible Interaction: Norepinephrine and Phosphatidic Acid

“ Noradrenaline induced a rise in both total and arachidonate-containing phosphatidic acid at both times as did vasopressin.”

“Norepinephrine NE ) selectively increases 32Pi incorporation into phosphatidylinositol (PI) and phosphatidic acid (PA) 60-200% over control levels.”

“3) Addition of acetylcholine and norepinephrine to the iridial processes and iris smooth muscle increased 32P labelling of phosphatidic acid and phosphatidylinositol of the tissues.”

“The increase in sensitivity to NE (12.5 μm) caused by denervation produced about 18% increase in the TPI effect and a 25% increase in the 32P labelling of PA , but not PI.”

“Our data suggest that in the iris muscle norepinephrine increases the turnover of PhA and PhI phosphorus by stimulating the hydrolysis of endogenous PhA or PhI. or both, to form more membraneous diglyceride.”

“… norepinephrine … phosphatidic acid and phosphatidylinositol, in general propranolol caused the following changes: (a) it stimulated by 2- to 6-fold the labelling of phosphatidic acid and …, (c) it inhibited appreciably the incorporation of [ 14 C]glucose, [ 14 C]glycerol, [ 14 C]acetate and 32 Pi into phosphatidylcholine and phosphatidylethanoalmine.”

“Furthermore, norepinephrine at concentrations of 3 μM and 30 μM produced 1.6 times and 3 times stimulation of the phosphatidic acid of the denervated muscle respectively.”

“The increase in the 32P labeling of PhA and PhI in the presence of norepinephrine or acetylcholine, which ranged from 2- to 6-fold, was found to be time- and concerntration-dependent.”

“Pretreatment with propranolol inhibited noradrenaline‐induced contractions and further addition of phosphatidic acid augmented this inhibition.”