Translation of clock rhythmicity into neural firing in suprachiasmatic nucleus requires mGluR-PLCbeta4 signaling

Phospholipase C β4 (PLCβ4) is expressed in the suprachiasmatic nucleus (SCN), as well as in tissues in the circadian entrainment pathway, including the retina and the lateral geniculate nucleus in the mouse1,2. Using PLCβ4−/− mice, we previously reported that PLCβ4 is coupled to metabotropic glutamate receptors (mGluRs)3, which regulate the ionotropic glutamate responsiveness of SCN neurons, and thus were proposed to be involved in photic entrainment4. We show here that the group-I mGluR–PLCβ4 signaling pathway is involved in translating circadian oscillations of the molecular clock into rhythmic outputs of SCN neurons.