The Journal of Neuroscience, August 1, 2002, 22(15):6560-6569
Pituitary Adenylate Cyclase-Activating Polypeptide and Vasoactive
Intestinal Peptide Inhibit Dendritic Growth in Cultured Sympathetic
Neurons
Karen
Drahushuk1,
Terry
D.
Connell2, and
Dennis
Higgins1
Departments of 1 Pharmacology and Toxicology and
2 Microbiology and the Witebsky Center for Microbial
Pathogenesis and Immunology, State University of New York at Buffalo,
Buffalo, New York 14214
Pituitary adenylate cyclase-activating polypeptide (PACAP) and
vasoactive intestinal peptide (VIP) are related neuropeptides that are
released by the preganglionic sympathetic axons. These peptides have
previously been implicated in the regulation of sympathetic
neurotransmitter metabolism and cell survival in postganglionic sympathetic neurons. In this study we consider the possibility that
PACAP and VIP also affect the morphological development of these
neurons. Postganglionic rat sympathetic neurons formed extensive dendritic arbors after exposure to bone morphogenetic protein-7 (BMP-7)
in vitro. PACAP and VIP reduced BMP-7-induced dendritic growth by ~70-90%, and this suppression was maintained for 3 weeks. However, neither PACAP nor VIP affected axonal growth or cell survival.
The actions of PACAP and VIP appear to be mediated by PAC1 receptors because their effects were suppressed
by an antagonist that binds to PAC1 and
VPAC2 receptors (PACAP6-38), but not by an
antagonist that binds to the VPAC1 and VPAC2
receptors. Moreover, exposure to PACAP and VIP caused phosphorylation
and nuclear translocation of cAMP response element-binding protein, and
agents that increase the intracellular concentration of cAMP mimicked
the PACAP-induced inhibition of dendritic growth. These data suggest
that peptides released by preganglionic nerves modulate dendritic
growth in sympathetic neurons by a cAMP-dependent mechanism.
Key words:
vasoactive intestinal peptide; pituitary adenylate
cyclase activating polypeptide; BMP-7; cAMP; dendrite; sympathetic
Copyright © 2002 Society for Neuroscience 0270-6474/02/22156560-10$05.00/0