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Prostacyclin mediates hypoxic relaxation of bovine coronary arterial strips

Prostaglandins 21(4): 555-570

Prostacyclin mediates hypoxic relaxation of bovine coronary arterial strips

Bovine coronary arterial strips (BCA) exhibiting spontaneous tone, relax in response to a decrease in the pO2 of the bathing medium. Experiments were performed to determine if prostaglandins (PG) mediate the O2-induced changes in tension. BCA were equilibrated in Krebs-bicarbonate solution at C gassed with 95% O2, 5% CO2 and tension was measured isometrically. When the pO2 of the bathing medium was decreased, BCA exhibited reversible reductions in tension. Switching from 95% O2, 5% CO2 to 95% N2, 5% CO2 (anoxia) elicited an initial relaxation followed by a contraction. A change to 5% O2, 5% CO2, 90% N2 (hypoxia) was followed by a sustained relaxation. Re-introduction of O2 to anoxic strips produced a biphasic response: relaxation followed by contraction. Indomethacin or eicosatetraynoic acid (EYA) increased tone and inhibited the relaxation produced by anoxia or hypoxia. Indomethacin or EYA did not inhibit the relaxation of anoxic strips during re-introduction of O2, but did inhibit the contraction partially. Relaxation of arterial strips to arachidonic acid (AA) was similar to relaxation to prostacyclin (PGI2). Anoxia limited the relaxation of AA but not to PGI2. PG synthesis contributes to the basal tone and the hypoxia-induced relaxation of BCA. Hypoxia, unless severe, ddoes not prevent the conversion of AA to PGI2.

Accession: 006206624

Related references

Roberts, A.M.; Messina, E.J.; Kaley, G., 1981: Prostacyclin (PGI2) mediates hypoxic relaxation of bovine coronary arterial strips. Bovine coronary arterial strips (BCA) exhibiting spontaneous tone, relax in response to a decrease in the pO2 of the bathing medium. Experiments were performed to determine if prostaglandins (PGs) mediate the oxygen-induced changes in tension. BCA...

Holzmann, S.; Kukovetz, W.R.; Schmidt, K., 1980: Mode of action of coronary arterial relaxation by prostacyclin. Subsequent to previous observations suggesting a close association between the relaxing actions of PGI2 and its increasing effects on cyclic AMP levels in bovine coronary smooth muscle, evidence indicative of a transmitter function of cAMP in PGI2...

Kuroiwa M.; Aoki H.; Nishimura J.; Kobayashi S.; Kanaide H., 1992: Mechanisms for ethanol induced constriction and relaxation of porcine coronary arterial strips. Japanese Journal of Pharmacology 59(SUPPL 1): 226P

Holzmann, S., 1982: Endothelium-induced relaxation by acetylcholine associated with larger rises in cyclic GMP in coronary arterial strips. It was previously shown that the contractile response to acetylcholine (ACh) in bovine coronary arterial strips could be separated from the accompanying rises in cGMP in an opposite manner which suggested that this nucleotide may function as a rel...

Dusting, G.J.; Lattimer, N.; Moncada, S.; Vane, J.R., 1977: Prostaglandin X, the vascular metabolite of arachidonic acid responsible for relaxation of bovine coronary artery strips [proceedings. British Journal of Pharmacology 59(3): 443p-443p

Vegesna, R.V.; Diamond, J., 1986: Elevation of cyclic AMP by prostacyclin is accompanied by relaxation of bovine coronary arteries and contraction of rabbit aortic rings. The role of cyclic AMP (cAMP) in the control of vascular smooth muscle tension was examined by comparing the effects of prostacyclin (PGI2) on tension and cAMP levels in helical strips of bovine coronary arteries and in rabbit aortic rings, both d...

Mohazzab H.Kevin M.; Fayngersh, R.P.; Wolin, M.S., 1996: Potentiation of relaxation of bovine coronary arteries to post-hypoxic reoxygenation by an inhibitor of glutathione peroxidase. Circulation 94(8 SUPPL ): I17

Revtyak, G.E.; Johnson, A.R.; Campbell, W.B., 1988: Cultured bovine coronary arterial endothelial cells synthesize HETEs and prostacyclin. Arachidonic acid metabolism was examined in endothelial cells cultured from bovine coronary arteries. In culture, these cells exhibit specific characteristics of endothelial cells. They form a contact-inhibited monolayer with a cobblestone appeara...

Gruetter, C.A.; Barry, B.K.; McNamara, D.B.; Gruetter, D.Y.; Kadowitz, P.J.; Ignarro, L., 1979: Relaxation of bovine coronary artery and activation of coronary arterial guanylate cyclase by nitric oxide, nitroprusside and a carcinogenic nitrosoamine. The principal objective of this study was to test the hypothesis that nitroprusside relaxes vascular smooth muscle via the reactive intermediate, nitric oxide (NO), and that the biologic action of NO is associated with the activation of guanylate...

McNamara, D.B.; Hussey, J.L.; Kerstein, M.D.; Rosenson, R.S.; Hyman, A.L.; Kadowitz, P.J., 1984: Modulation of prostacyclin synthetase and unmasking of PGE2 isomerase in bovine coronary arterial microsomes. Prostacyclin (PGI2), a major product of prostaglandin endoperoxide (PGH2) metabolism in blood vessels, has potent vasodilator and platelet activity. Therefore, modulation of PGI2 synthetase activity is of prime physiological importance in the regu...