Human vasoactive intestinal peptide1 receptors expressed by stable transfectants couple to two distinct signaling pathways
Sreedharan, S.P.; Patel, D.R.; Xia, M.; Ichikawa, S.; Goetzl, E.J.
Biochemical and Biophysical Research Communications 203(1): 141-148
1994
ISSN/ISBN: 0006-291X PMID: 8074647 Document Number: 429271
Vasoactive intestinal peptide (VIP) is a potent neuropeptide mediator of central and peripheral nervous system function. A human VIP-1 receptor (HVR) cDNA clone was previously obtained from HT29 intestinal epithelial cells and lung tissue. Stably-transfected human embryonic kidney 293 cells and chinese hamster ovary (CHO) cells expressing about 10-6 HVRs per cell that bind (125I)VIP with a K-d of 0.2-0.8 nM, and specifically recognized by anti-HVR antibodies, were established and characterized. VIP induced increases in intracellular cAMP levels ((cAMP)-i) dose-dependently with an EC-50 of 0.2 nM in 293 and CHO stable transfectants and concurrently evoked dose-dependent increases in intracellular calcium concentrations ((Ca-2+)-i), as determined by fluorescence-dye spectroscopy. Untransfected 293 and CHO cells showed minimal binding or intracellular effects of VIP; however, native VIP-1 receptors of HT29 cells also increased (cAMP)-i and (Ca-2+)-i in dose-dependent responses to VIP. Thus recombinant and native human VIP-1 receptors both couple to two distinct signal transduction pathways within a single cell type.