The effects of paracetamol and indomethacin on the action of centrally administered noradrenaline (NA) on the blood pressure, heart rate and rectal body temperature were studied in rats. It was demonstrated that both these substances increased NA effect on the arterial blood pressure and heart rate but caused no changes in NA effect on body temperature. These results suggest a modulating action of prostaglandins in the central nervous system on the functions of the centres regulating cardiovascular functions.