Abstract
The effects of (+/-)-1-O-octadecyl-2-acetyl-glyceryl-3-phosphorylcholine (octadecyl-AGPC) were studied in three types of aortic vascular smooth muscle preparations, namely, strips, rubbed and unrubbed rings, and an atrial preparation in normotensive rats. In the resting tension state, octadecyl-AGPC did not elicit significant contractions in either rubbed or unrubbed ring preparations at concentrations lower than 1 X 10(-4) M. However, at a concentration of 3 X 10(-4) M, octadecyl-AGPC markedly contracted both types of ring preparations. This contractile response was partially antagonized by pretreatment with reserpine and completely blocked by phentolamine (1 X 10(-6) M). In preparations contracted with noradrenaline (NA), octadecyl-AGPC elicited biphasic responses in intact ring preparations; an initial relaxation followed by contraction. Octadecyl-AGPC induced only a slight contraction in strips and a slight relaxation in the rubbed ring preparation. Octadecyl-AGPC did not elicit any significant effect on chronotropy or inotropy at concentrations up to 3 X 10(-5) M. When the concentration was 1 X 10(-4) M, octadecyl-AGPC produced significant positive chronotropic and inotropic effects on spontaneously beating right and electrically driven left atrial preparations, respectively. Both effects were blocked by propranolol (5 X 10(-8) M); reserpine pretreatment antagonized only the chronotropic response. In [3H]-dihydroalprenolol [( 3H]-DHA) binding studies, octadecyl-AGPC had a Kd of 427.85 microM and thus was much less potent than isoprenaline (Kd = 465.10 nM) or propranolol (Kd = 4.4 nM) in displacing [3H]-DHA in rat cardiac membrane preparations.(ABSTRACT TRUNCATED AT 250 WORDS)
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Baker S. P., Potter L. T. Cardiac beta-adrenoceptors during normal growth of male and female rats. Br J Pharmacol. 1980 Jan;68(1):65–70. doi: 10.1111/j.1476-5381.1980.tb10699.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cervoni P., Herzlinger H., Lai F. M., Tanikella T. A comparison of cardiac reactivity and beta-adrenoceptor number and affinity between aorta-coarcted hypertensive and normotensive rats. Br J Pharmacol. 1981 Nov;74(3):517–523. doi: 10.1111/j.1476-5381.1981.tb10459.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cheng Y., Prusoff W. H. Relationship between the inhibition constant (K1) and the concentration of inhibitor which causes 50 per cent inhibition (I50) of an enzymatic reaction. Biochem Pharmacol. 1973 Dec 1;22(23):3099–3108. doi: 10.1016/0006-2952(73)90196-2. [DOI] [PubMed] [Google Scholar]
- Demopoulos C. A., Pinckard R. N., Hanahan D. J. Platelet-activating factor. Evidence for 1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine as the active component (a new class of lipid chemical mediators). J Biol Chem. 1979 Oct 10;254(19):9355–9358. [PubMed] [Google Scholar]
- FURCHGOTT R. F., BHADRAKOM S. Reactions of strips of rabbit aorta to epinephrine, isopropylarterenol, sodium nitrite and other drugs. J Pharmacol Exp Ther. 1953 Jun;108(2):129–143. [PubMed] [Google Scholar]
- Furchgott R. F., Zawadzki J. V. The obligatory role of endothelial cells in the relaxation of arterial smooth muscle by acetylcholine. Nature. 1980 Nov 27;288(5789):373–376. doi: 10.1038/288373a0. [DOI] [PubMed] [Google Scholar]
- Goldstein B. M., Lai F. M., Herzlinger H., Cervoni P. Disposition of catecholamines in cardiovascular tissues of aorta coarcted hypertensive rats. Life Sci. 1982 Oct 11;31(15):1633–1638. doi: 10.1016/0024-3205(82)90056-x. [DOI] [PubMed] [Google Scholar]
- Lai F. M., Shepherd C. A., Cervoni P., Wissner A. Hypotensive and vasodilatory activity of (+/-) 1-o-octadecyl-2-acetyl glyceryl-3-phosphorylcholine in the normotensive rat. Life Sci. 1983 Mar 7;32(10):1159–1166. doi: 10.1016/0024-3205(83)90122-4. [DOI] [PubMed] [Google Scholar]
- Muirhead E. E. Antihypertensive functions of the kidney: Arthur C. Corcoran memorial lecture. Hypertension. 1980 Jul-Aug;2(4):444–464. doi: 10.1161/01.hyp.2.4.444. [DOI] [PubMed] [Google Scholar]