Involvement of capsaicin-sensitive nerves in regulation of insulin secretion and glucose tolerance in conscious mice

Sven Karlsson, Anton J.W. Scheurink, Anton B. Steffens, Bo Ahrén

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Abstract

The impact of sensory nerves in glucose-stimulated insulin secretion and glucose tolerance was investigated in conscious mice treated neonatally with either capsaicin (Cap) or vehicle (Veh). At 10-12 wk after Cap, both the early (1 min) insulin secretory response to intravenous glucose (2.8 mmol/kg) (by 67%) and glucose elimination were potentiated (P <0.05). In contrast, basal insulin, glucagon, and glucose were not affected by Cap. Plasma norepinephrine and epinephrine levels did not differ between Cap- and Veh-treated animals, whereas the increase in plasma insulin levels normally induced by alpha-adrenoceptor blockade by phentolamine was absent after Cap treatment. In isolated islets, the insulin secretory response to glucose (20 mmol/l), carbachol (0.1 mmol/l), or phentolamine (0.5 mmol/l) was not affected after Cap. It is concluded that sensory denervation by Cap results in increased glucose tolerance, which is in part because of a potentiated early insulin response to glucose. This potentiation does not seem secondary to altered plasma catecholamine levels or to altered islet secretory capacity. The results suggest rather that Cap-sensitive nerves, by a local effector function and/or as the afferent loop of a neural reflex, exert inhibitory influences on insulin secretion.

Original languageEnglish
Pages (from-to)R1071-R1077
Number of pages7
JournalThe American Journal of Physiology - Regulatory, Integrative and Comparative Physiology
Volume267
Issue number4
Publication statusPublished - Oct-1994

Keywords

  • ISLETS
  • B CELLS
  • AFFERENT NERVES
  • GLUCAGON
  • CATECHOLAMINES
  • GENE-RELATED PEPTIDE
  • SENSORY NEURONS
  • RATS
  • PANCREAS
  • PLASMA
  • MOUSE
  • IMMUNOREACTIVITY
  • PHENTOLAMINE
  • INHIBITION

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