Central cardiovascular and thermal effects of prostaglandin D2 in rats.

Prostaglandin D2 (PGD2) is the most common prostaglandin type of the rat brain. Recently a neuromodulator role for PGD2 has been suggested. In the present work the central cardiovascular and thermal effects of PGD2 were studied in urethane-anaesthetised rats. When administered at the doses of 0.001-10 micrograms/rat into the lateral cerebral ventricle (i.c.v.), PGD2 slightly increased the blood pressure, heart rate and body temperature. The highest dose caused also an initial hypotensive effect. Upon intravenous injections PGD2 (0.1-10 micrograms/rat) initially decreased and then weakly increased the blood pressure but had only negligible effects on heart rate and body temperature. Central pretreatment with sodium meclofenamate or indomethacin (1 mg/rat i.c.v.) antagonised effectively all the recorded central effects of PGD2. The central cardiovascular and thermal effects of PGD2 were much weaker than those obtained earlier with other prostaglandins, such as PGF2 alpha and PGE2. Therefore, in spite of its abundance in the brain PGD2 may not be very important for the central cardiovascular and thermal regulation in the rat.