Acetylcholine is released at all of the following junctions, EXCEPT:
The terminal sympathetic fibers to the hea use norepinephrine as do most sympathetic nerve endings. All preganglionic and parasympathetic postganglionic fibers release acetylcholine.Norepinephrine is synthesized from tyrosine in the cytoplasm and packaged into vesicles of postganglionic fibers. It is released exocytosis. NE is terminated by reuptake into the postganglionic nerve ending, diffusion from receptor sites, or metabolism by the enzymes monoamine oxidase (MAO), and catechol-O-methyltransferase (COMT) . NE is utilized in sympathetic postganglionic neurons. Ref: Beck-Yoo K. (2012). Chapter 19. The Nervous System. In L.W. Janson, M.E. Tischler (Eds), The Big Picture: Medical Biochemistry.
Terminal sympathetic fibers to the hea
Terminal parasympathetic fibers
Somatic efferents to skeletal muscles
Parasympathetic ganglia.
Terminal sympathetic fibers to the hea