Delta (Phospho) Sleep Inducing Peptide (DSIP-P), a peptide that promotes sustained sleep, induces changes in circadian locomotor activity in rats [1][2][3].

Delta (Phospho) Sleep Inducing Peptide, at concentrations ranging from 20 to 300 nM, enhances the activity of rat pineal N-acetyltransferase (NAT), which is stimulated by norepinephrine in vitro [3].

Delta (Phospho) Sleep Inducing Peptide (0.1 nmol/kg; i.v.; once daily for 4 times) alters circadian locomotor activity [1]. Administered into the third cerebroventricle of male rats at 20 or 200 pmol/kg immediately before the dark period, it enhances slow-wave and paradoxical sleep during the dark period, with 200 pmol/kg doing so without reducing sleep latency [2].