title: Glucose-induced islet blood flow increase in rats: interaction between nervous and metabolic mediators.
abstract: This study investigated the mechanisms for glucose-induced islet blood flow increase in rats. The effects of adenosine, adenosine receptor antagonists, and vagotomy on islet blood flow were evaluated with a microsphere technique. Vagotomy prevented the islet blood flow increase expected 3, 10, and 20 min after injection of glucose, whereas theophylline (a nonspecific adenosine receptor antagonist) prevented the islet blood flow increase from occurring 10 and 20 min after glucose administration. Administration of selective adenosine receptor antagonists suggested that the response to theophylline was mediated by A1 receptors. Exogenous administration of adenosine did not affect islet blood flow, but local accumulation of adenosine, induced by the adenosine uptake inhibitor dipyridamole, caused a doubling of islet blood flow. In conclusion, the increased islet blood flow seen 3 min after induction of hyperglycemia is caused by the vagal nerve, whereas the increase in islet blood perfusion seen at 10 and 20 min after glucose administration is caused by both the vagal nerve and adenosine.
authors.affiliation: Department of Medical Cell Biology, Uppsala University, SE-751 23 Uppsala, Sweden. Per-Ola.Carlsson@medcellbiol.uu.se
authors.forename: Per-Ola
authors.initials: PO
authors.lastname: Carlsson
authors.forename: Richard
authors.initials: R
authors.lastname: Olsson
authors.forename: Orjan
authors.initials: O
authors.lastname: Källskog
authors.forename: Birgitta
authors.initials: B
authors.lastname: Bodin
authors.forename: Arne
authors.initials: A
authors.lastname: Andersson
authors.forename: Leif
authors.initials: L
authors.lastname: Jansson
mesh_terms: D000241:Adenosine / Q000494:pharmacology; D000818:Animals; D004176:Dipyridamole / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology*; D007515:Islets of Langerhans / Q000098:blood supply*; D008297:Male; D058915:Purinergic P1 Receptor Antagonists; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000187:drug effects; D013805:Theobromine / Q000031:analogs & derivatives* / Q000494:pharmacology; D013806:Theophylline / Q000494:pharmacology; D014628:Vagotomy; D014665:Vasodilator Agents / Q000494:pharmacology; D014970:Xanthines / Q000494:pharmacology
chemical_list: D058915:Purinergic P1 Receptor Antagonists; D014665:Vasodilator Agents; D014970:Xanthines; C057837:3,7-dimethyl-1-propargylxanthine; D004176:Dipyridamole; C051360:1,3-dipropyl-8-cyclopentylxanthine; D013806:Theophylline; D005947:Glucose; D000241:Adenosine; D013805:Theobromine