[Relationships between ethanol-induced sleep and aspirin, indomethacin or PGE2 in inbred rats]

It is known that prostaglandin synthetase inhibitors (PGSI) inhibit ethanol (EtOH)-induced sleep in mice, and that EtOH increases production of prostaglandins (PGs). EtOH hypnosis and effects of prostaglandins on EtOH-induced sleeping in inbred rats were examined. The EtOH (3 g/kg, i.p.)-induced sleep time was significantly longer in Fischer 344 (F344) than in Lewis (LEW); blood EtOH concentrations (BAC) on awaking were significantly lower in F344 than in LEW. When aspirin (ASP) and indomethacin (IND) were given 15 and 30 min prior to EtOH administration, respectively, both strains significantly slept shorter than those receiving no PGSI. The BACs on awaking in both strains receiving PGSI were higher than those receiving no PGSI. When LEW and F344 rats were pretreated with PGE2 (0.05-0.5mg/kg, s.c.) 30 min prior to EtOH administration, either strain slept significantly shorter as compared with those receiving EtOH alone. The BACs on awaking were significantly higher in the animals receiving the combination of PGE2 and EtOH than those receiving EtOH alone. These results suggest that there is the strain difference between F344 and LEW in ethanol-induced sleep, and that PGs may, in part, play a role in EtOH-induced sleep in LEW and F344.