English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

A variety of evidence now suggests that excitatory amino acid receptors mediate the effects of light on the circadian system of mammals. However, the ACh agonist carbachol is the only agent that has been reported to “mimic” the phase-shifting effects of light in vivo. Because the other published evidence for the involvement of ACh in light-mediated phase shifts is weak, we have referred to this situation as “the carbachol paradox.” In the present study, we found that the administration of NMDA receptor antagonists could prevent carbachol- induced phase shifts of the circadian rhythm of wheel-running activity recorded from the hamster. In addition, we found that carbachol-induced phase shifts, unlike those produced by light, are not accompanied by induction of Fos-like immunoreactivity in the suprachiasmatic nucleus (SCN). Our data are simply explained by the assumption that the intraventricular administration of carbachol causes phase shifts through a pathway distinct from that of light. Alternatively, if carbachol is acting via the light input pathway, then it must do so by a mechanism independent of Fos induction in the SCN. In either case, elucidating the mechanisms by which carbachol acts in the circadian system may provide novel insights into the cellular events by which phase shifts are generated.

Phase-shifting mechanisms in the mammalian circadian system: new light on the carbachol paradox