Vasoactive intestinal polypeptide phase-advances the rat suprachiasmatic nuclei circadian pacemaker in vitro via protein kinase A and mitogen-activated protein kinase

Neurosci Lett. 2004 Mar 25;358(2):91-4. doi: 10.1016/j.neulet.2003.12.114.

Abstract

The firing activity of suprachiasmatic nuclei (SCN) neurones in vitro shows a circadian rhythm with the peak in average firing frequency during the middle of the projected day. Vasoactive intestinal polypeptide (VIP), which is abundant in the rat SCN, phase-advances the time of peak in SCN neuronal activity when applied in vitro during the late projected night; an effect most likely mediated via the VPAC(2) receptor. Employing extracellular single-unit electrophysiology, we investigated the influence of protein kinase A (PKA) inhibitor KT5720 or mitogen-activated protein kinase kinase (MAPKK) inhibitor U0126 on phase advances evoked during the late projected night by VIP or Ro 25-1553, a VPAC(2) receptor agonist. Both inhibitors blocked VIP or Ro 25-1553-induced phase advances, indicating that the late-night resetting actions of VIP via the VPAC(2) receptor require PKA and MEK.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biological Clocks / drug effects
  • Biological Clocks / physiology
  • Circadian Rhythm / drug effects*
  • Circadian Rhythm / physiology
  • Cyclic AMP-Dependent Protein Kinases / antagonists & inhibitors
  • Cyclic AMP-Dependent Protein Kinases / physiology*
  • Enzyme Inhibitors / pharmacology
  • Male
  • Mitogen-Activated Protein Kinases / antagonists & inhibitors
  • Mitogen-Activated Protein Kinases / physiology*
  • Rats
  • Rats, Wistar
  • Suprachiasmatic Nucleus / drug effects*
  • Suprachiasmatic Nucleus / enzymology
  • Vasoactive Intestinal Peptide / pharmacology*

Substances

  • Enzyme Inhibitors
  • Vasoactive Intestinal Peptide
  • Cyclic AMP-Dependent Protein Kinases
  • Mitogen-Activated Protein Kinases