Disrupted Neuronal Activity Rhythms in the Suprachiasmatic Nuclei of Vasoactive Intestinal Polypeptide-Deficient Mice
Copyright policy )Disrupted Neuronal Activity Rhythms in the Suprachiasmatic Nuclei of Vasoactive Intestinal Polypeptide-Deficient Mice
Vasoactive intestinal polypeptide (VIP), acting via the VPAC2receptor, is a key signaling pathway in the suprachiasmatic nuclei (SCN), the master clock controlling daily rhythms in mammals. Most mice lacking functional VPAC2receptors are unable to sustain behavioral rhythms and lack detectable SCN electrical rhythms in vitro. Adult mice that do not produce VIP (VIP/PHI−/−) exhibit less severe alterations in wheel-running rhythms, but the effects of this deficiency on the amplitude, phasing, or periodicity of their SCN cellular rhythms are unknown. To investigate this, we used suction electrodes to extracellularly record multiple- and single-unit electrical activity in SCN brain slices from mice with varying degrees of VIP deficiency, ranging from wild-type (VIP/PHI+/+) to heterozygous (VIP/PHI+/−) and VIP/PHI−/−animals. We found decreasing proportions of rhythmic cells in SCN slices from VIP/PHI+/+(∼91%, n = 23) through VIP/PHI-/+(∼71%, n = 28) to VIP/PHI−/−mice (62%; n = 37) and a parallel trend toward decreasing amplitude in the remaining rhythmic cells. SCN neurons from VIP/PHI−/−mice exhibited a broad range in the period and phasing of electrical rhythms, concordant with the known alterations in their behavioral rhythms. Further, treatment of VIP/PHI−/−slices with a VPAC2receptor antagonist significantly reduced the proportion of oscillating neurons, suggesting that VPAC2receptors still become activated in the SCN of these mice. The results establish that VIP is important for appropriate periodicity and phasing of SCN neuronal rhythms and suggest that residual VPAC2receptor signaling promotes rhythmicity in adult VIP/PHI−/−mice.
- University of Salford United Kingdom
Male, Mice, Knockout, Neurons, Analysis of Variance, Chi-Square Distribution, Action Potentials, In Vitro Techniques, Circadian Rhythm, Mice, Inbred C57BL, Mice, Animals, Receptors, Vasoactive Intestinal Peptide, Type II, Female, Suprachiasmatic Nucleus, Vasoactive Intestinal Peptide
Male, Mice, Knockout, Neurons, Analysis of Variance, Chi-Square Distribution, Action Potentials, In Vitro Techniques, Circadian Rhythm, Mice, Inbred C57BL, Mice, Animals, Receptors, Vasoactive Intestinal Peptide, Type II, Female, Suprachiasmatic Nucleus, Vasoactive Intestinal Peptide
citations This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).104 popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.Top 10% influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).Top 10% impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.Top 10%
Citations provided by BIP!Popularity provided by BIP!