Tissue elevation of which of the following cause vasoconstriction :

Ans. D. Ca2+Vascular Control by lons and Other Chemical Factors Guyton 12th(SAE)/269An increase in calcium ion concentration causes vasoconstriction.An increase in potassium ion concentration,.within the physiological range, causes vasodilation.An increase in magnesium ion concentration causes powerful vasodilation.An increase in hydrogen ion concentration (decrease in pH) causes dilation of the aerioles.Anions that have significant effects on blood vessels are acetate and citrate.An Increase in carbon dioxide concentration causes moderate vasodilation in most tissues but marked vasodilation in the brain.