title: Sympathetic nerve stimulation versus pancreatic norepinephrine infusion in the dog: 1). Effects on basal release of insulin and glucagon.
abstract: We investigated whether pancreatic norepinephrine (NE) infusions could reproduce the inhibition of insulin secretion and the stimulation of glucagon secretion observed during sympathetic nerve stimulation in halothane-anesthetized dogs. Three minutes of stimulating the sympathetic nerves (8 Hz, 1 msec, 10 mA, n = 6) surrounding the pancreatic artery decreased both the blood flow in the superior pancreatic vein (SPV) (delta = -1.7 +/- 0.6 ml/min, P less than 0.05) and the basal pancreatic output of immunoreactive insulin (IRI) (delta = -79 +/- 5%, P less than 0.001). SPV levels of NE increased by 683 +/- 177 pg/ml (P less than 0.02). Infusion of NE into the superior pancreatic artery at the low dose of 12 ng/min (n = 6) reproduced this increase of SPV levels of NE (delta = +740 +/- 130 pg/ml; P less than 0.01) and caused a small reduction of SPV blood flow (delta = -1.0 +/- 0.4 ml/min, P less than 0.05), but did not change pancreatic IRI (delta = -26 +/- 16%, NS). The medium dose of NE (120 ng/min, n = 6) reproduced the nerve stimulation-induced decrease of SPV blood flow (delta = -1.5 +/- 0.2 ml/min; P less than 0.01) and increased the SPV NE levels by 6,306 +/- 1,839 pg/ml (P less than 0.02), yet did not decrease pancreatic IRI output (delta = +62 +/- 49%, NS). The high dose of NE (1,200 ng/min, n = 6) produced an extreme increment of SPV NE levels (delta = +180,000 +/- 44,000 pg/ml, P less than 0.001) and a much larger reduction of SPV blood flow (delta = -3.7 +/- 0.7 ml/min, P less than 0.01) than did nerve stimulation, yet still did not inhibit insulin output (delta = -13 +/- 46%, NS). Ten minutes of sympathetic nerve stimulation increased the pancreatic output of immunoreactive glucagon (IRG) by 1435 +/- 419 pg/min (P less than 0.02). Pancreatic IRG output increased as well during infusion of NE for 10 min at both 12 ng/min (by 575 +/- 205 pg/min, P less than 0.05) and 120 ng/min (by 718 +/- 231 pg/min, P less than 0.05). In marked contrast, during infusion of NE at 1200 ng/min, pancreatic IRG output decreased (by 400 +/- 190 pg/min, P less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)
authors.forename: B
authors.initials: B
authors.lastname: Ahrén
authors.forename: R C
authors.initials: RC
authors.lastname: Veith
authors.forename: G J
authors.initials: GJ
authors.lastname: Taborsky
mesh_terms: D000818:Animals; D001158:Arteries / Q000502:physiology; D004285:Dogs; D004558:Electric Stimulation; D005934:Glucagon / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D009638:Norepinephrine / Q000097:blood / Q000494:pharmacology*; D010179:Pancreas / Q000098:blood supply / Q000294:innervation / Q000378:metabolism*; D012039:Regional Blood Flow / Q000187:drug effects; D013564:Sympathetic Nervous System / Q000502:physiology*; D014680:Veins
chemical_list: D007328:Insulin; D005934:Glucagon; D009638:Norepinephrine