title: Pituitary adenylate cyclase activating polypeptide (PACAP) redistributes the blood within the pancreas of anesthetized rats.
abstract: The aim of the study was to evaluate the effects of pituitary adenylate cyclase activating polypeptide-38 (PACAP-38) on splanchnic blood flow in anesthetized rats. For this purpose, either PACAP-38 dissolved in saline or saline alone was injected intravenously 5 (10 nmol/kg body weight (bw) PACAP-38) and 30 min (5 or 10 nmol/kg) before measurements. The blood flow to the whole pancreas, islets, duodenum and colon was then measured with a microsphere technique. The higher dose of PACAP-38 slightly increased blood glucose concentrations at both 5 and 30 min after administration, whereas the lower had no effect. Both doses of PACAP-38 induced a transient initial decrease in mean arterial blood pressure. The lower dose of PACAP-38 decreased fractional islet blood flow 30 min after administration, but did not affect the other blood flows. The higher dose of the peptide (10 nmol/kg bw) caused an increase in whole pancreatic blood flow at both 5 and 30 min after administration, whereas islet blood flow was only increased at the former time. At both time points PACAP-38 redistributed the blood flow within the pancreas in favour of the exocrine pancreas. This resulted in a decreased fractional islet blood flow, i.e., the fraction of whole pancreatic blood flow diverted through the islets. At 5 min after PACAP-38 administration duodenal blood flow was decreased, whereas after 30 min no effects on duodenal or colonic blood flow were observed. Administration of a VIP antagonist intravenously (20 nmol/kg bw) decreased the PACAP-38-induced pancreatic blood flow increase and intrapancreatic redistribution. When only the VIP antagonist was given both pancreatic and islet blood decreased in concert. It is concluded that administration of PACAP-38 induces a blood flow increase in the pancreas, preferably in the exocrine parts of the gland, by actions mediated by PACAP-38 receptors shared with VIP.
authors.affiliation: Department of Medical Cell Biology, Uppsala University, Sweden.
authors.forename: P O
authors.initials: PO
authors.lastname: Carlsson
authors.forename: C G
authors.initials: CG
authors.lastname: Ostenson
authors.forename: S
authors.initials: S
authors.lastname: Efendic
authors.forename: U
authors.initials: U
authors.lastname: Langel
authors.forename: L
authors.initials: L
authors.lastname: Jansson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001775:Blood Circulation / Q000187:drug effects; D001786:Blood Glucose / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D008297:Male; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000494:pharmacology*; D010179:Pancreas / Q000187:drug effects*; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D010902:Pituitary Gland / Q000201:enzymology; D051381:Rats; D017207:Rats, Sprague-Dawley; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D011979:Receptors, Pituitary Hormone / Q000378:metabolism*; D018005:Receptors, Vasoactive Intestinal Peptide / Q000037:antagonists & inhibitors / Q000378:metabolism; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: C495403:Adcyap1 protein, rat; D001786:Blood Glucose; D009479:Neuropeptides; D010455:Peptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D011979:Receptors, Pituitary Hormone; D018005:Receptors, Vasoactive Intestinal Peptide; D014665:Vasodilator Agents; D014660:Vasoactive Intestinal Peptide