TY - JOUR
T1 - Different Roles for VIP Neurons in the Neonatal and Adult Suprachiasmatic Nucleus
AU - Mazuski, Cristina
AU - Chen, Samantha P.
AU - Herzog, Erik D.
N1 - Publisher Copyright:
© 2020 The Author(s).
PY - 2020/10/1
Y1 - 2020/10/1
N2 - The suprachiasmatic nucleus (SCN) drives circadian rhythms in locomotion through coupled, single-cell oscillations. Global genetic deletion of the neuropeptide Vip or its receptor Vipr2 results in profound deficits in daily synchrony among SCN cells and daily rhythms in locomotor behavior and glucocorticoid secretion. To test whether this phenotype depends on vasoactive intestinal polypeptide (VIP) neurons in the SCN, we ablated VIP SCN neurons in vivo in adult male mice through Caspase3-mediated induction of the apoptotic pathway in cre-expressing VIP neurons. We found that ablation of VIP SCN neurons in adult mice caused a phenotype distinct from Vip- and Vipr2-null mice. Mice lacking VIP neurons retained rhythmic locomotor activity with a shortened circadian period, more variable onsets, and decreased duration of daily activity. Circadian hormonal outputs, specifically corticosterone rhythms, were severely dampened. In contrast, deletion of neonatal SCN VIP neurons dramatically reduced circadian gene expression in the cultured SCN, mimicking the effects of global deletion of Vip or Vipr2. These results suggest that SCN VIP neurons play a role in lengthening circadian period and stimulating the daily surge in glucocorticoids in adults and in synchronizing and sustaining daily rhythms among cells in the developing SCN.
AB - The suprachiasmatic nucleus (SCN) drives circadian rhythms in locomotion through coupled, single-cell oscillations. Global genetic deletion of the neuropeptide Vip or its receptor Vipr2 results in profound deficits in daily synchrony among SCN cells and daily rhythms in locomotor behavior and glucocorticoid secretion. To test whether this phenotype depends on vasoactive intestinal polypeptide (VIP) neurons in the SCN, we ablated VIP SCN neurons in vivo in adult male mice through Caspase3-mediated induction of the apoptotic pathway in cre-expressing VIP neurons. We found that ablation of VIP SCN neurons in adult mice caused a phenotype distinct from Vip- and Vipr2-null mice. Mice lacking VIP neurons retained rhythmic locomotor activity with a shortened circadian period, more variable onsets, and decreased duration of daily activity. Circadian hormonal outputs, specifically corticosterone rhythms, were severely dampened. In contrast, deletion of neonatal SCN VIP neurons dramatically reduced circadian gene expression in the cultured SCN, mimicking the effects of global deletion of Vip or Vipr2. These results suggest that SCN VIP neurons play a role in lengthening circadian period and stimulating the daily surge in glucocorticoids in adults and in synchronizing and sustaining daily rhythms among cells in the developing SCN.
KW - caspase
KW - suprachiasmatic nucleus
KW - vasoactive intestinal peptide
KW - vasopressin
UR - http://www.scopus.com/inward/record.url?scp=85089966709&partnerID=8YFLogxK
U2 - 10.1177/0748730420932073
DO - 10.1177/0748730420932073
M3 - Article
C2 - 32536240
AN - SCOPUS:85089966709
SN - 0748-7304
VL - 35
SP - 465
EP - 475
JO - Journal of Biological Rhythms
JF - Journal of Biological Rhythms
IS - 5
ER -