Fig. 4
The presumed neuroanatomical mechanism of the arousal effects of Ca2+ in the dorsal raphe nucleus (DRN). Microinjection of CaCl2 in the DRN promotes wakefulness and suppresses sleep. By activating protein kinase C (PKC) or calmodulin-dependent kinase II (CaMKII) mediated signal transduction, the intra-DRN application of Ca2+ might potentiate serotonin (5-HT) synthesis, which up-regulates serotonergic functions in endogenous sleep-wake regulating pathway, causing decreased GABAergic neurons activity in the ventrolateral preoptic nucleus (VLPO), increased orexinergic neurons activity in the perifornical nucleus (Pef) and increased noradrenergic neurons activity in the locus coeruleus (LC)