Pharmacologically distinct vasoactive intestinal peptide binding sites: CNS localization and role in embryonic growth.
In vitro autoradiography with [125I]vasoactive intestinal peptide revealed that the vasoactive intestinal peptide analogue, stearyl-norleucine17 vasoactive intestinal peptide, reported to be inactive at adenylyl cyclase-linked receptors in astrocytes, displaced a subset of vasoactive intestinal peptide binding sites on rat brain sections. These sites were widespread in adult rat brains and enriched in the olfactory bulb and thalamus, and corresponded to previously demonstrated GTP-insensitive vasoactive intestinal peptide binding sites. Stearyl-norleucine17 vasoactive intestinal peptide also identified receptors in rat lung and liver. In the adult brain, the stearyl-norleucine analog displaced only GTP-insensitive vasoactive intestinal peptide binding sites. In contrast, stearyl-norleucine17 vasoactive intestinal peptide-displaceable sites in the embryonic day 9 mouse appeared to include both GTP-sensitive and GTP-insensitive binding sites. This observation suggested the presence of an embryonic vasoactive intestinal peptide receptor with distinct pharmacological properties. Treatment of whole cultured mouse embryos with stearyl-norleucine17 vasoactive intestinal peptide resulted in stimulation of embryonic growth, with the stearyl-norleucine analog equipotent to vasoactive intestinal peptide, but less efficacious at higher concentrations (10(-7) M). Embryonic growth was inhibited by pituitary adenylyl cyclase-activating peptide and 8-bromoadenosine 3',5'-cyclic monophosphate. In addition, 8-bromoadenosine 3',5'-cyclic monophosphate inhibited stearyl-norleucine17 vasoactive intestinal peptide-stimulated growth. The results of the current study support the hypothesis that vasoactive intestinal peptide regulation of early postimplantation embryonic growth occurs, at least in part, independently of adenylyl cyclase stimulation.
Hill
J M
JM
Section on Developmental and Molecular Pharmacology, Laboratory of Developmental Neurobiology, National Institute of Child Health and Human Development, Bethesda, MD 20892, USA. jh139h@nih.gov
Lee
S J
SJ
Dibbern
D A
DA
Fridkin
M
M
Gozes
I
I
Brenneman
D E
DE
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D001345:Autoradiography; D001665:Binding Sites / Q000187:drug effects / Q000502:physiology; D001921:Brain / Q000033:anatomy & histology / Q000196:embryology / Q000378:metabolism; D002490:Central Nervous System / Q000033:anatomy & histology / Q000196:embryology* / Q000378:metabolism*; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D008297:Male; D051379:Mice; D009479:Neuropeptides / Q000494:pharmacology; D009924:Organ Culture Techniques; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D051381:Rats; D017207:Rats, Sprague-Dawley; D018005:Receptors, Vasoactive Intestinal Peptide / Q000187:drug effects / Q000502:physiology*; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
C495402:Adcyap1 protein, mouse; C495403:Adcyap1 protein, rat; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D018005:Receptors, Vasoactive Intestinal Peptide; C086770:stearyl-norleucine(17)-vasoactive intestinal peptide; D015124:8-Bromo Cyclic Adenosine Monophosphate; D006165:Guanylyl Imidodiphosphate; D014660:Vasoactive Intestinal Peptide