VIP -- a 'very Important Peptide' in the Sympathetic Nervous System?

Vasoactive intestinal peptide (VIP) is involved in the control of smooth muscle activity, blood flow and exo- as well as endocrine secretion. More recent work has elucidated the effects of this peptide on central and peripheral neurons. These studies suggest that VIP is an important modulator of cell growth, differentiation and neuronal survival during development of the sympathetic nervous system. VIP is also expressed in a subset of adult postganglionic sympathetic neurons. Furthermore, VIP is induced in an additional neuronal subpopulation of the rat superior cervical ganglion after axotomy. The mechanisms leading to increased VIP expression and its possible role during sympathetic nerve regeneration are currently being elucidated. This review summarizes the distribution, regulation and functions of VIP in cervical sympathetic ganglia of higher vertebrates.