Possible involvement of the S-adenosyl-L-homocysteine metabolites, adenosine and L-homocysteine, in sleep in rats.
The effects of i.p. injections of adenosine (Ado) and homocysteine at 17.00 h were tested on the rat sleep-waking cycle. Administration of 7 and 50 mg/kg of Ado resulted in a significant increase in sleep in otherwise saline male rats during the environmental-dark period (18.00-06.00 h). Increments of paradoxical sleep were maximal with the smaller dose of Ado. The larger dose increased slow-wave sleep during the first 2 h. In contrast, administration of homocysteine (7 mg/kg) had no effect while a larger dose (50 mg/kg) induced a slight but significant long-lasting decrease of paradoxical sleep. These results were compared with those previously obtained with S-adenosyl-L-homocysteine (SAH), an intracellular precursor of Ado and L-homocysteine. It is proposed that the reported hypnotic action of exogenous SAH in rats could be mediated by Ado receptors.
D000241:Adenosine / Q000008:administration & dosage / Q000502:physiology*; D000818:Animals; D004569:Electroencephalography; D006710:Homocysteine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000502:physiology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012435:S-Adenosylhomocysteine / Q000378:metabolism*; D012894:Sleep Stages / Q000187:drug effects / Q000502:physiology*; D012895:Sleep, REM / Q000187:drug effects; D013997:Time Factors
D006710:Homocysteine; D012435:S-Adenosylhomocysteine; D000241:Adenosine