RESUMO
Objective To investigate the effect of extragenous adenosine(AD) by microinjection in the orexinergic area of rat lateral hypothalamus(LH) on the sleep-wake cycle.Methods A total of 14 male SD rats were given 1,10 or 20 nmol AD and artificial cerebrospinal fluid(aCSF) as own control through three different models of microinjections into the LH.Their electroencephalogram(EEG) and electromyogram(EMG) were recorded by a polygraph recording instrument to observe the changes of sleep-wake after microinjections.Results AD administration to LH at doses of 1,10 and 20 nmol decreased the total amount of wakefulness by 84%,62% and 60% fold during that first 3-hour recording period and concomitantly increased non rapid eye movement(NREM) and REM sleep,when compared with aCSF treatment.The sleep-inducing effect was maintained even in 3 hour after the 20 nmol AD microinjection.The maximal sleep-inducing effect was obtained at the 20 nmol dose of AD administration into the orexinergic LH(P