Concentration of prostaglandin D2 in cerebrospinal fluid exhibits a circadian alteration in conscious rats.
Cerebrospinal fluid (CSF) was withdrawn from the cisterna magna of unanesthetized conscious rats (n = 14) through a chronically implanted catheter, and prostaglandins (PGs) D2, E2, and F2 alpha were measured. From each rat, CSF samples were taken at different clock-hours of the day (1000, 1400, and 1800 hr) and night (2200, 0200, and 0600 hr) in succession at 76-hour intervals. The concentration of PGD2 alone exhibited a significant circadian fluctuation, with its peak value at 1400 hr (mean +/- SEM: 1197 +/- 361 pg/ml) and its lowest level at 0600 hr (438 +/- 106 pg/ml). Thus, the mean level of PGD2 during the daytime (903 +/- 162 pg/ml) was significantly higher than that during the night (503 +/- 78 pg/ml). The results obtained are consistent with the postulated role of PGD2, acting in the surface layer of the rostral basal forebrain, as an endogenous factor to promote sleep.
Pandey
H P
HP
Osaka Bioscience Institute, Furuedai, Japan.
Ram
A
A
Matsumura
H
H
Hayaishi
O
O
D000704:Analysis of Variance; D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D002946:Cisterna Magna; D008297:Male; D015230:Prostaglandin D2 / Q000134:cerebrospinal fluid*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012890:Sleep / Q000502:physiology*
D015230:Prostaglandin D2