Effect of L-methionine on contractile response, calcium influx and calcium channel blocking agents in the rat aorta.
L-Methionine incubated with aorta strips and S-adenosyl-L-methionine incubated with aorta membranes methylate membrane phospholipids. L-Methionine enhances the contractile response of helical strips of rat aorta to KCl. L-Methionine also enhances the slow component of the contractile response of rat aorta to norepinephrine associated with influx of exogenous calcium. L-Homocysteinethiolactone inhibits methylation of membrane phospholipids and depresses the contractile response to KCl and to norepinephrine. L-Methionine enhances and L-homocysteinethiolactone depresses KCl-stimulated influx of calcium into rat aorta strips. L-Methionine has no effect on calcium efflux. Tested against calcium channel blocking agents, L-methionine reduces the inhibition caused by diltiazem and chlorpromazine but not that caused by TMB 8 or verapamil. It is postulated that methylated intermediates of phospholipid methylation enhance the function of membrane calcium channels.
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D066298:In Vitro Techniques; D008715:Methionine / Q000494:pharmacology*; D008745:Methylation; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D009638:Norepinephrine / Q000494:pharmacology; D010743:Phospholipids / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
D002121:Calcium Channel Blockers; D010743:Phospholipids; D011189:Potassium Chloride; D008715:Methionine; D002118:Calcium; D009638:Norepinephrine