The canine sympathetic neuropeptide galanin: A neurotransmitter in pancreas, a neuromodulator in liver

G. J. Taborsky, B. E. Dunning, Peter J Havel, B. Ahren, S. Kowalyk, M. R. Boyle, C. B. Verchere, D. G. Baskin, T. O. Mundinger

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

Our laboratory has investigated the role of the neuropeptide galanin in the sympathetic neural control of both the canine endocrine pancreas and liver. Galanin mRNA and peptide were found in the neuronal cell bodies of the celiac ganglion, which projects fibers to both organs. Galanin fibers formed dense networks around the islets. Galanin was released from these nerves and the amount released appeared sufficient to markedly inhibit basal insulin secretion. We therefore propose that galanin is a sympathetic neurotransmitter in canine endocrine pancreas. Galanin was also found in hepatic nerves usually co-localized with tyrosine hydroxylase, a sympathetic marker. Further, intraportal administration of the sympathetic neurotoxin, 6- hydroxydopamine, abolished galanin staining in the hepatic parenchyma. We evaluated the role of galanin in mediating the actions of sympathetic nerves to increase hepatic glucose production and decrease hepatic arterial conductance. Local infusion of synthetic galanin had little effect by itself, but it did potentiate the action of norepinephrine to stimulate hepatic glucose production, demonstrating a neuromodulatory action. In contrast, galanin had no effect on hepatic arterial blood flow. We therefore propose that in the liver galanin functions as a neuromodulator of norepinephrine's metabolic action.

Original languageEnglish (US)
Pages (from-to)351-354
Number of pages4
JournalHormone and Metabolic Research
Volume31
Issue number5
StatePublished - 1999
Externally publishedYes

Keywords

  • Hepatic Glucose Production
  • Insulin Secretion
  • Norepinephrine

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology

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    Taborsky, G. J., Dunning, B. E., Havel, P. J., Ahren, B., Kowalyk, S., Boyle, M. R., Verchere, C. B., Baskin, D. G., & Mundinger, T. O. (1999). The canine sympathetic neuropeptide galanin: A neurotransmitter in pancreas, a neuromodulator in liver. Hormone and Metabolic Research, 31(5), 351-354.