Daily electrical activity in the master circadian clock of a diurnal mammal

Document Type

Article

Publication Date

11-1-2021

Abstract

Circadian rhythms in mammals are orchestrated by a central clock within the suprachiasmatic nuclei (SCN). Our understanding of the electrophysiological basis of SCN activity comes overwhelmingly from a small number of nocturnal rodent species, and the extent to which these are retained in day-active animals remains unclear. Here, we recorded the spontaneous and evoked electrical activity of single SCN neurons in the diurnal rodent Rhabdomys pumilio, and developed cutting-edge data assimilation and mathematical modeling approaches to uncover the underlying ionic mechanisms. As in nocturnal rodents, R. pumilio SCN neurons were more excited during daytime hours. By contrast, the evoked activity of R. pumilio neurons included a prominent suppressive response that is not present in the SCN of nocturnal rodents. Our modeling revealed and subsequent experiments confirmed transient subthreshold A-type potassium channels as the primary determinant of this response, and suggest a key role for this ionic mechanism in optimizing SCN function to accommodate R. pumilio’s diurnal niche.

Identifier

85120156370 (Scopus)

Publication Title

Elife

External Full Text Location

https://doi.org/10.7554/eLife.68179

e-ISSN

2050084X

PubMed ID

34845984

Volume

10

Grant

DMS 155237

Fund Ref

US-UK Fulbright Commission

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