Distribution of mRNAs for pituitary adenylate cyclase-activating polypeptide (PACAP), PACAP receptor, vasoactive intestinal polypeptide (VIP), and VIP receptors in the rat superior cervical ganglion

The distribution of mRNAs for pituitary adenylate cyclase-activating polypeptide (PACAP), PACAP receptor (PACAP-R), vasoactive intestinal polypeptide (VIP) and two subtypes of VLP receptors (VIP1-R and VIP2-R) was examined by in situ hybridization in the superior cervical ganglion (SCG) of the adult rat. PACAP-R mRNA was expressed intensely in virtually all principal neurons. PACAP mRNA was expressed in approximately half of the principal neurons, where the levels of expression vary extensively. Intense expression of VLP mRNA was observed only in a few principal neurons. Neither VIP1-R mRNA nor VIP2-R mRNA was detected in SCG cells. These findings suggest that PACAP, but not VIP, may function as a paracrine or autocrine regulatory factor through PACAP-R in the principal neurons of the SCG. (C) 1997 Elsevier Science Ireland Ltd.