Output from VIP cells of the mammalian central clock regulates daily physiological rhythms

Nat Commun. 2020 Mar 19;11(1):1453. doi: 10.1038/s41467-020-15277-x.

Abstract

The suprachiasmatic nucleus (SCN) circadian clock is critical for optimising daily cycles in mammalian physiology and behaviour. The roles of the various SCN cell types in communicating timing information to downstream physiological systems remain incompletely understood, however. In particular, while vasoactive intestinal polypeptide (VIP) signalling is essential for SCN function and whole animal circadian rhythmicity, the specific contributions of VIP cell output to physiological control remains uncertain. Here we reveal a key role for SCN VIP cells in central clock output. Using multielectrode recording and optogenetic manipulations, we show that VIP neurons provide coordinated daily waves of GABAergic input to target cells across the paraventricular hypothalamus and ventral thalamus, supressing their activity during the mid to late day. Using chemogenetic manipulation, we further demonstrate specific roles for this circuitry in the daily control of heart rate and corticosterone secretion, collectively establishing SCN VIP cells as influential regulators of physiological timing.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials / drug effects
  • Action Potentials / physiology
  • Animals
  • Bicuculline / pharmacology
  • Channelrhodopsins / chemistry
  • Channelrhodopsins / genetics
  • Channelrhodopsins / metabolism
  • Circadian Clocks / drug effects
  • Circadian Clocks / physiology*
  • Circadian Rhythm / physiology*
  • Corticosterone / blood
  • Corticosterone / metabolism
  • Electrodes, Implanted
  • Female
  • GABA-A Receptor Antagonists / pharmacology
  • GABAergic Neurons / drug effects
  • GABAergic Neurons / metabolism*
  • Heart Rate / physiology
  • Male
  • Mice
  • Mice, Transgenic
  • Models, Animal
  • Suprachiasmatic Nucleus / cytology
  • Suprachiasmatic Nucleus / physiology*
  • Vasoactive Intestinal Peptide / antagonists & inhibitors
  • Vasoactive Intestinal Peptide / genetics
  • Vasoactive Intestinal Peptide / metabolism*

Substances

  • Channelrhodopsins
  • GABA-A Receptor Antagonists
  • Vasoactive Intestinal Peptide
  • Corticosterone
  • Bicuculline