Abstract
1 The aim of the study was to determine the mechanism of the hypotension and bradycardia produced by prostacyclin (PGI2). 2 Haemodynamic studies were carried out in nineteen open-chest beagle dogs anaesthetized with chloralose. PGI2 was infused intravenously or into the left atrium. 3 Infusions of PGI2 either intravenously or into the left atrium equally reduced arterial pressure and total peripheral resistance but bradycardia was greater after infusion into the left atrium. 4 Comparison of effects of PGI2 with those of prostaglandin E2 (PGE2) showed that although left atrial infusions both reduced aortic pressure and total peripheral resistance, PGE2 always increased heart rate, cardiac output and maximum acceleration. 5 Similar effects were observed with sodium nitroprusside except that it always caused tachycardia and reduced stroke volume. 6 Atropine (0.05 or 1 mg/kg i.v.) reduced or reversed the bradycardia induced by PGI2 but its hypotensive effects were reduced only after 1 mg/kg atropine. After vagotomy changes in cardiac output, stroke volume and maximum acceleration were increased, the hypotensive effects of PGI2 were reduced and the bradycardia was reversed; effects induced by PGE2 were not significantly altered. 7 The hypotension induced by prostacyclin is due to two components, a direct relaxation of vascular smooth muscle and a reflex, non-cholinergic vasodilatation. The bradycardia is reflex in nature and is partially mediated by the vagus pathway.
Full text
PDFSelected References
These references are in PubMed. This may not be the complete list of references from this article.
- Armstrong J. M., Chapple D., Dusting G. J., Hughes R., Moncada S., Vane J. R. Cardiovascular actions of prostacyclin (PCI2) in chloralose anaesthetized dogs [proceedings]. Br J Pharmacol. 1977 Sep;61(1):136P–136P. [PMC free article] [PubMed] [Google Scholar]
- Armstrong J. M., Lattimer N., Moncada S., Vane J. R. Comparison of the vasodepressor effects of prostacyclin and 6-oxo-prostaglandin F1alpha with those of prostaglandin E2 in rats and rabbits. Br J Pharmacol. 1978 Jan;62(1):125–130. doi: 10.1111/j.1476-5381.1978.tb07014.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bunting S., Gryglewski R., Moncada S., Vane J. R. Arterial walls generate from prostaglandin endoperoxides a substance (prostaglandin X) which relaxes strips of mesenteric and coeliac ateries and inhibits platelet aggregation. Prostaglandins. 1976 Dec;12(6):897–913. doi: 10.1016/0090-6980(76)90125-8. [DOI] [PubMed] [Google Scholar]
- Chung D. C., Chamberlain J. H., Seed R. G. The effect of haemodynamic changes on maximum blood flow acceleration at the aortic root in the anaesthetized, open-chest dog. Cardiovasc Res. 1974 May;8(3):362–372. doi: 10.1093/cvr/8.3.362. [DOI] [PubMed] [Google Scholar]
- Coleridge H. M., Coleridge J. C., Ginzel K. H., Baker D. G., Banzett R. B., Morrison M. A. Stimulation of 'irritant' receptors and afferent C-fibres in the lungs by prostaglandins. Nature. 1976 Dec 2;264(5585):451–453. doi: 10.1038/264451a0. [DOI] [PubMed] [Google Scholar]
- Dusting G. J., Chapple D. J., Hughes R., Moncada S., Vane J. R. Prostacyclin (PGI2) induces coronary vasodilatation in anaesthetised dogs. Cardiovasc Res. 1978 Dec;12(12):720–730. [PubMed] [Google Scholar]
- Dusting G. J., Moncada S., Vane J. R. Prostacyclin (PGX) is the endogenous metabolite responsible for relaxation of coronary arteries induced by arachindonic acid. Prostaglandins. 1977 Jan;13(1):3–15. doi: 10.1016/0090-6980(77)90037-5. [DOI] [PubMed] [Google Scholar]
- Dusting G. J., Moncada S., Vane J. R. Recirculation of prostacyclin (PGI2) in the dog. Br J Pharmacol. 1978 Oct;64(2):315–320. doi: 10.1111/j.1476-5381.1978.tb17307.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ferreira S. H., Vane J. R. Prostaglandins: their disappearance from and release into the circulation. Nature. 1967 Dec 2;216(5118):868–873. doi: 10.1038/216868a0. [DOI] [PubMed] [Google Scholar]
- Fitzpatrick T. M., Alter I., Corey E. J., Ramwell P. W., Rose J. C., Kot P. A. Cardiovascular responses to PGI2 (prostacyclin) in the dog. Circ Res. 1978 Feb;42(2):192–194. doi: 10.1161/01.res.42.2.192. [DOI] [PubMed] [Google Scholar]
- Gryglewski R. J., Korbut R., Ocetkiewicz A. Generation of prostacyclin by lungs in vivo and its release into the arterial circulation. Nature. 1978 Jun 29;273(5665):765–767. doi: 10.1038/273765a0. [DOI] [PubMed] [Google Scholar]
- Hughes R. Continuous measurement of peripheral vascular resistance and circulatory function. Med Biol Eng. 1971 Nov;9(6):603–610. doi: 10.1007/BF02474640. [DOI] [PubMed] [Google Scholar]
- Johnson R. A., Lincoln F. H., Thompson J. L., Nidy E. G., Mizak S. A., Axen U. Synthesis and sterochemistry of prostacyclin and synthesis of 6-ketoprostagliandin F1alpha. J Am Chem Soc. 1977 Jun 8;99(12):4182–4184. doi: 10.1021/ja00454a060. [DOI] [PubMed] [Google Scholar]
- Jones R. L., Kane K. A., Ungar A. Cardiovascular actions of prostaglandin C in the cat and dog. Br J Pharmacol. 1974 Jun;51(2):157–160. doi: 10.1111/j.1476-5381.1974.tb09642.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kot P. A., Johnson M., Ramwell P. W., Rose J. C. Effects of ganglionic and beta-adrenergic blockade on cardiovascular responses to the bisenoic prostaglandins and their precursor arachidonic acid. Proc Soc Exp Biol Med. 1975 Sep;149(4):953–957. doi: 10.3181/00379727-149-38934. [DOI] [PubMed] [Google Scholar]
- Lefer A. M., Ogletree M. L., Smith J. B., Silver M. J., Nicolaou K. C., Barnette W. E., Gasic G. P. Prostacyclin: a potentially valuable agent for preserving myocardial tissue in acute myocardial ischemia. Science. 1978 Apr 7;200(4337):52–54. doi: 10.1126/science.345441. [DOI] [PubMed] [Google Scholar]
- Moncada S., Korbut R., Bunting S., Vane J. R. Prostacyclin is a circulating hormone. Nature. 1978 Jun 29;273(5665):767–768. doi: 10.1038/273767a0. [DOI] [PubMed] [Google Scholar]
- Mullane K. M., Dusting G. J., Salmon J. A., Moncada S., Vane J. R. Biotransformation and cardiovascular effects of arachidonic acid in the dog. Eur J Pharmacol. 1979 Mar 1;54(3):217–228. doi: 10.1016/0014-2999(79)90080-3. [DOI] [PubMed] [Google Scholar]