Adenosine analogues modulate the incidence of sleep apneas in rats

The effects of adenosine A1 and A2 agonists on spontaneous central sleep apneas in rats have been examined by simultaneously monitoring sleep and respiration in freely moving unanesthetized animals. Intraperitoneal administration of 1.0 mg/kg of the A1 receptor agonist R(-)N6-L-(2-phenyl-isopropyl)adenosine (L-PIA) and 150 and 300 micrograms/kg of 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamido-adenosine hydrochloride (CGS 21680), a selective A2 agonist, decreased the apnea index (AI) during sleep. Within a sleep period, AI increased over time in both control and drug-treated animals. For both agonists, doses effective in reducing AI also significantly reduced sleep efficiency.