Hypertension due to chronic blockade of P-I-purinoceptors

I Long-term treatment of rats with 1,3-dipropyl-8-sulphophenylxanthine (DPSPX), a nonselective antagonist of adenosine receptors, causes a hypertensive state. 2 In DPSPX-hypertensive rats, prejunctional alpha(2)-adrenoceptors become supersensitive to the selective alpha(2)-adrenoceptor agonist UK-14,304, while postjunctional adrenoceptor-mediated responses are not changed; furthermore, prejunctional beta-adrenoceptor-mediated facilitation of noradrenaline release is also enhanced. 3 In DPSPX-hypertensive rats, there are important morphological alterations of the small arteries, their lumina appearing strongly reduced and occasionally occluded by proliferation of the intimal cells. 4 In DPSPX-hypertensive rats, there is an increase in plasma renin, and captopril prevents not only the development of the hypertension but also the morphological changes in the arteries. 5 Other important changes occur in DPSPX-hypertensive rats: an alteration of the adrenergic regulation of the cardiac functions and an enhancement of perivascular neurotransmission. 6 These results suggest that adenosine may play an important role in the development of some kinds of human hypertension.