Loss ofdexras1Alters Nonphotic Circadian Phase Shifts and Reveals a Role for the Intergeniculate Leaflet (IGL) in Gene-Targeted Mice

Loss of Dexras1 in gene-targeted mice leads to enhanced nonphotic phase shifts throughout the subjective day.

• Dexras1 deficiency results in complex changes to phase-dependent responses to light cycles.
• Arousal induces significant phase shifts in mutant mice, particularly in the subjective day.
• Unusual phase advances occur in the late subjective night, despite minimal arousal effects.
• Bilateral lesions of the intergeniculate leaflet eliminate both nonphotic and light-induced phase shifts during the subjective day.
• The expression of FOS-like protein in the suprachiasmatic nucleus is unaffected by both light and arousal stimulation in the subjective day.
• Dexras1 is associated with the regulation of various signal-transduction pathways linked to circadian entrainment.

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