Yonsei Med J.  1995 Dec;36(6):487-496. 10.3349/ymj.1995.36.6.487.

Effects of adenosine tetraphosphate (ATPP) on vascular tone in the isolated rat aorta

• Lee JW
• Kong ID
• Park KS
• Jeong SW

• KMID: 699860
• DOI: http://doi.org/10.3349/ymj.1995.36.6.487

Abstract

Effects of a platelet-released, naturally occurring nucleotide, adenosine 5'-tetraphosphate (ATPP) on vascular tone were analyzed in the isolated rat aorta. Under resting tension ATPP (1 approximately 100 microM) elicited concentration-dependent contractions in endothelium-intact aortic rings in contrast to the concentration-dependent relaxation with ATP. In endothelium-denuded aortic rings, ATPP induced contraction, as ATP did, but with a greater potency. alpha, beta-methylene ATP (APCPP 50 microM), a P2x-purinoceptor antagonist, significantly inhibited ATPP- as well as ATP-induced contractions in the endothelium-denuded preparations suggesting that ATPP acts via P2x-purinoceptors. ATPP (10 approximately 100 microM) relaxed precontracted aortic rings with an intact endothelium in a concentration-dependent manner. This effect of ATPP was 3.7 fold less potent than that of ATP. However, after P2x-purinoceptor blockade, the effect became identical between the two nucleotides. Reactive blue 2, a selective antagonist of P2x-purinoceptors, significantly attenuated the ATPP-induced relaxation with no change in the ATP-induced relaxation. These results indicated that the rat aortic endothelium contains heterogeneous populations of P2-purinoceptors (possibly P2y and nucleotide receptors). Since ATPP shows dual effects depending upon the vascular tension, it may play a significant role in the physiological regulation of vascular tone.

Keyword

Adenosine tetraphosphate; ATP; P2-purinoceptor; nucleotide receptor; endothelium; vascular smooth muscle; alpha beta-methylene ATP; reactive blue 2

MeSH Terms

Animal
Aorta/*drug effects/physiology
Dinucleoside Phosphates/*pharmacology
Female
In Vitro
Male
Rats
Rats, Sprague-Dawley
Receptors, Purinergic P2/metabolism
Support, Non-U.S. Gov't
Vasoconstriction/*drug effects
Vasodilation/drug effects