Insulin reduces excitation in gastric-related neurons of the dorsal motor nucleus of the vagus

Camille B. Blake, Bret N. Smith

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


The dorsal motor nucleus of the vagus (DMV) in the caudal brain stem is composed mainly of preganglionic parasympathetic neurons that control the sub diaphragmatic viscera and thus participates in energy homeostasis regulation. Metabolic pathologies, including diabetes, can disrupt vagal circuitry and lead to gastric dysfunction. Insulin receptors (IRs) are expressed in the DMV, and insulin crosses the blood-brain barrier and is transported into the brain stem. Despite growing evidence that insulin action in the brain is critical for energy homeostasis, little is known about insulin's action in the DMV. We used whole cell patch-clamp recordings in brain stem slices to identify effects of insulin on membrane and synaptic input properties of DMV neurons, including a subset of gastric-related cells identified subsequent to injection of a retrograde label into the gastric wall. Insulin application significantly reduced the frequency of spontaneous and miniature excitatory, but not inhibitory postsynaptic currents, with no change in amplitude (P < 0.05). Insulin also directly hyperpolarized the membrane potential (-4.2 ±1.3 mV; P < 0.05) and reduced action potential firing (P < 0.05). Insulin effects were eliminated in the presence of a ATP-dependent K + (K ATP) channel antagonist tolbutamide (200 (μM), or the phosphatidylinositol 3-kinase (PI3K) inhibitor wortman-nin (100 nM), suggesting that insulin inhibition of excitatory input to gastric-related DMV neurons was mediated by K ATP channels and depended on PI3K activity. Insulin regulation of synaptic input in the DMV may influence autonomic visceral regulation and thus systemic glucose metabolism.

Original languageEnglish
Pages (from-to)R807-R814
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Issue number8
StatePublished - Oct 15 2012


  • Autonomic
  • Diabetes
  • Glutamate
  • Nucleus tractus solitarius
  • Patch-clamp
  • Vagus

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


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