Circadian regulation of GABAA receptor function by CKI epsilon-CKI delta in the rat suprachiasmatic nuclei.

The type A GABA receptors are thought to mediate synchronization of clock cell activity within the suprachiasmatic nuclei (SCN). Here we report that casein kinases I epsilon and delta (CKI epsilon and CKI delta), the crucial clock regulators, form a complex with GABA(A) receptors and inhibit the receptors' function within the SCN according to a circadian rhythm. These results indicate that circadian variation of the kinase-receptor association may mediate regulation of GABA(A) receptor function by CKI epsilon-CKI delta in the SCN.