Cellular Mg++ accumulation is altered by extracellular Na+ and directly affects agonist-induced mobilization of Ca++ in vascular smooth muscle.

摘要: Effects of altered Na+, Ca++ and Mg++ concentrations on 45Ca 28Mg distribution binding as well changes in cellular mobilization by added norepinephrine (NE) were examined the rabbit aortic media-intimal layer. Uptake at high affinity sites was decreased much more than uptake Ca++. Substitution Na+ affects primarily extracellular (La+++-accessible) sites. Muscles pre-loaded with incubation a low-Na+ solution (75% replaced isosmotically sucrose) for 30 min followed 90 exposure to similar also containing 15 mM MgCl2. These tissues, upon examination normal (154 mM) Na+-containing solution, indicated retention that cellular, high-affinity fraction important NE-induced contractile response. Accordingly, release from this site associated tension responses NE attenuated these muscles. results suggest variations concentration modulate subsequent activator agonists through alterations content vascular smooth muscle.