Why does acetylcholine causes vaso-dilation?
In some muscle tissue acetylcholine causes vaso-dilation, but
not all. Norepinephrine is the opposite competor/effector of
acetylcholine. Acetylcholine is present in all preganglionic
fibers, both parasympathetic and sympathetic. Acetylcholine is
present in postganglionic parasympatic fibers, where norepinephrine
is present in the postganglionic sympathetic fibers. In some
tissues acetylcholine causes constriction. Can also reduce heart
rate vi the vagus nerve. Acetylcholine is the only neurotransmitter
used in the somatic nervous system! Acetylcholine can effect
vasodilation by several mechanisms, including activation of
endothelial nitric oxide (NO) synthase and prostaglandin (PG)
production. In human skin, exogenous Acetylcholine increases both
skin blood flow and bioavailable NO levels, but the relative
increase is much greater in skin blood flow than NO. So this may
lead us to speculate that acetylcholine may dilate cutaneous blood
vessels through PGs, as well as NO. In some muscle tissue
acetylcholine causes vaso-dilation, but not all. Norepinephrine is
the opposite competor/effector of acetylcholine. Acetylcholine is
present in all preganglionic fibers, both parasympathetic and
sympathetic. Acetylcholine is present in postganglionic
parasympatic fibers, where norepinephrine is present in the
postganglionic sympathetic fibers. In some tissues acetylcholine
causes constriction. Can also reduce heart rate vi the vagus nerve.
Acetylcholine is the only neurotransmitter used in the somatic
nervous system! Acetylcholine can effect vasodilation by several
mechanisms, including activation of endothelial nitric oxide (NO)
synthase and prostaglandin (PG) production. In human skin,
exogenous Acetylcholine increases both skin blood flow and
bioavailable NO levels, but the relative increase is much greater
in skin blood flow than NO. So this may lead us to speculate that
acetylcholine may dilate cutaneous blood vessels through PGs, as
well as NO.