Inhibitory responses to retinohypothalamic tract stimulation in the circadian clock of the diurnal rodent Rhabdomys pumilio.

ABSTRACT: In both diurnal and nocturnal mammals, the timing of activity is regulated by the central circadian clock of the suprachiasmatic nucleus (SCN). The SCN is synchronized to the external light cycle via the retinohypothalamic tract (RHT). To investigate potential differences in light processing between nocturnal mice and the diurnal rodent Rhabdomys pumilio, we mimicked retinal input by stimulation of the RHT ex vivo. Using Ca²⁺ imaging, we observed excitations as well as inhibitions of SCN neurons in response to electrical RHT stimulation. In mice, the vast majority of responses were excitatory (85%), whereas in Rhabdomys, the proportion of excitatory and inhibitory responses was similar (51% excitatory, 49% inhibitory). Glutamate blockers AP5 and CNQX blocked the excitatory respo

SUBMITTER: Schoonderwoerd RA 

PROVIDER: S-EPMC9544711 | biostudies-literature | 2022 Aug

REPOSITORIES: biostudies-literature