Circadian clocks are complex biochemical systems that cycle with a period of approximately 24 hours. They integrate temporal information regarding phasing of the solar cycle, and adjust their phase so as to synchronize an organism's internal state to the local environmental day and night. Nocturnal light is the dominant regulator of this entrainment. In mammals, information about nocturnal light is transmitted by @entity2227 released from retinal projections to the circadian clock in the suprachiasmatic nucleus of the hypothalamus. Clock resetting requires the activation of ionotropic @entity2227 receptors, which mediate @entity141 influx. The response induced by such activation depends on the clock's temporal state: during early night it delays the clock phase, whereas in late night the clock phase is advanced. To investigate this differential response, we sought signalling elements that contribute solely to phase delay. We analysed intracellular @entity460 -channel @entity8452 receptors, which mediate coupled @entity141 signalling. Depletion of intracellular @entity141 stores during early night blocked the effects of @entity2227 . Activators of @entity8452 receptors induced phase resetting only in early night; inhibitors selectively blocked delays induced by light and @entity2227 . These findings implicate the release of intracellular @entity141 through @entity8452 receptors in the light-induced phase delay of the circadian clock restricted to the early night.

A neuronal XXXX receptor mediates light-induced phase delays of the circadian clock.

@entity141 :: ('CHEBI:29108', 'Chemical') :: ['Ca2+'] @entity8452 :: ('MESH:D012433', 'Chemical') :: ['ryanodine'] @entity2227 :: ('CHEBI:29987', 'Chemical') :: ['glutamate'] @entity460 :: ('MESH:D002118', 'Chemical') :: ['calcium']
@entity8452 :: (MESH:D012433,Chemical) :: ['ryanodine']
