Effects of kynurenic acid and ketamine on neonatal sleep in rats.

Kynurenic acid and ketamine are, besides non-specific actions, antagonists of excitatory acidic amino acids in the rat brain. At intraperitoneal doses of 300 mg/kg (1.6 mmol/l) and 5 mg/kg (18 mmol/l), respectively, they are equipotent antagonists of N-methyl-D-aspartate receptors. We studied the acute effects of ketamine and kynurenic acid, at these doses, on sleep patterns of rats during the second and third postnatal weeks with the so called static charge sensitive mattress (SCSB). Both kynurenic acid and ketamine decreased active sleep; ketamine additionally increased quiet state and kynurenic acid increased waking. The decrease in active sleep may be related to glutaminergic NMDA and serotonergic responses in the rat brain but non-specific actions and interactions with other transmitter systems are also involved.