Abstract
1 Intravenous injections of urotensin I regularly caused a long-lasting, dose-related, lowering of blood pressure and an increase in heart rate in conscious rats, or a reduction in perfusion pressure in the isolated hind limb of the rat.
2 After subcutaneous administration, the hypotensive effect of urotensin I was greater in extent and in duration (> 24 hours).
3 Anaesthesia with ether, chloralose, pentobarbitone and thiobarbitone caused a decrease in blood pressure and only slightly diminished the hypotensive effect of urotensin.
4 Mecamylamine, hexamethonium, atropine, phenoxybenzamine, propranolol and diphenhydramine did not alter the effect of urotensin in conscious rats or in the isolated hind limb, although the effects of the respective agonists, i.e. nicotine, acetylcholine, noradrenaline, isoprenaline and histamine were inhibited.
5 In conscious rats, pressor effects of adrenaline, noradrenaline, nicotine and angiotensin II, and depressor effects of acetylcholine and bradykinin, were decreased or inhibited, whereas the hypotensive effect of phenoxybenzamine was potentiated by previous administration of urotensin I. Carotid occlusion reflex was partially inhibited by lower doses of urotensin and abolished by higher doses in rats lightly anaesthetized with chloralose. Urotensin elicited postural hypotension in rats anaesthetized with pentobarbitone.
6 The increase in heart rate produced by urotensin was not affected by phenoxybenzamine, but was abolished by propranolol or ganglion blocking agents (mecamylamine or hexamethonium).
7 It is concluded that urotensin elicits hypotension in the rat by a direct dilatory action on the resistance vessels causing a simultaneous reflex tachycardia.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bern H. A., Lederis K. A reference preparation for the study of active substances in the caudal neurosecretory system of teleosts. J Endocrinol. 1969 Sep;45(1 Suppl):xi–xii. [PubMed] [Google Scholar]
- Bertaccini G., Cei J. M., Erspamer V. Occurrence of physalaemin in extracts of the skin of Physalaemus fuscumaculatus and its pharmacological actions on extravascular smooth muscle. Br J Pharmacol Chemother. 1965 Oct;25(2):363–379. doi: 10.1111/j.1476-5381.1965.tb02056.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bertaccini G., Cei J. M., Erspamer V. The action of physalaemin on the systemic arterial blood pressure of some experimental animals. Br J Pharmacol Chemother. 1965 Oct;25(2):380–391. doi: 10.1111/j.1476-5381.1965.tb02057.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chan D. K., Jones I. C., Ponniah S. Studies on the pressor substances of the caudal neurosecretory system of teleost fish: bioassay and fractionation. J Endocrinol. 1969 Oct;45(2):151–159. doi: 10.1677/joe.0.0450151. [DOI] [PubMed] [Google Scholar]
- Fogelman F., Grundy H. F. A comparison of the cardiovascular actions of AQ 110 with those of isoprenaline and salbutamol. Br J Pharmacol. 1970 Feb;38(2):416–432. doi: 10.1111/j.1476-5381.1970.tb08529.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- KOBAYASHI H., UEMURA H., OOTA Y., ISHII S. Cholinergic substance in the caudal neurosecretory storage organ of fish. Science. 1963 Aug 23;141(3582):714–716. doi: 10.1126/science.141.3582.714-a. [DOI] [PubMed] [Google Scholar]
- LOCKETT M. F. Identification of an isoprenaline-like substance in extracts of adrenal glands. Br J Pharmacol Chemother. 1954 Dec;9(4):498–505. doi: 10.1111/j.1476-5381.1954.tb00868.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LOCKETT M. F. The transmitter released by stimulation of the bronchial sympathetic nerves of cats. Br J Pharmacol Chemother. 1957 Mar;12(1):86–96. doi: 10.1111/j.1476-5381.1957.tb01367.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lederis K. Teleostean urophysis: stimulation of contractions of bladder of the trout Salmo gairdnerii. Science. 1969 Mar 21;163(3873):1327–1328. doi: 10.1126/science.163.3873.1327. [DOI] [PubMed] [Google Scholar]
- ROBERTS D., LOCKETT M. F. A note on the influence of a metabolite of adrenaline on water diuresis in rats. J Pharm Pharmacol. 1961 Oct;13:631–633. doi: 10.1111/j.2042-7158.1961.tb11881.x. [DOI] [PubMed] [Google Scholar]
- Zelnik P. R., Lederis K. Chromatographic separation of urotensins. Gen Comp Endocrinol. 1973 Apr;20(2):392–400. doi: 10.1016/0016-6480(73)90193-7. [DOI] [PubMed] [Google Scholar]