Alteration of blood pressure response to arachidonic acid in diabetic rats

ABSTRACT

The dose dependency and mechanism of arachidonic acid [AA]-induced decrement in systemic blood pressure [BP] was investigated in diabetic rats, versus their controls Intravenous [I.V.] injection of 0.5-2 mg AA into diabetic rats [2 weeks after a single S.C. injection of alloxan, 175 mg/kg] caused dose dependent decrement in BP. The diabetic rats displayed decreased responsiveness to the hypotensive effect of AA compared to control rats. AA hypotensive responses were completely abolished by indomethacin [5 mg/kg I.V.]. Prostaglandin F2gamma [PGF2gamma], 20 ug, and norepinephrine [NE], 4 ug, increased BP whereas acetyloholine [ACh], 2 ug, lowered it in both diabetic and control rats. No significant differences were detected for the effects of the above mentioned drugs between the two groups. The findings indicate that AA is converted into cyclo-oxygenase derived products with predilection to formation of excess vasoconstrictor[s] metabolites and/or depressed vasodilator[s] production