Abstract
1. The DP receptors located on platelets and vasculature were examined in a human washed platelet preparation and in isolated rings of rabbit external jugular vein. 2. A series of eight novel bicyclic compounds were studied for their effects in the two assays. Seven produced agonism, inhibition of aggregation or vascular relaxation, and one compound was 'silent' in both assays. 3. The operational model of agonism (Black & Leff, 1983) was fitted simultaneously to concentration-effect curve data for the seven agonist compounds. The affinity and efficacy estimates so obtained were tested for similarity between the two tissues by analysis of variance, showing that the model could be fitted to both sets of data by assuming the same relative affinity and efficacy values. However, absolute affinity estimates were consistently lower in the vascular preparation. 4. Analysis of two of the seven agonists as antagonists was also possible. This provided pKB estimates which supported the agonist affinity estimates. The eighth compound was also analysed as an antagonist. It, like the other seven, demonstrated a difference in affinity between the two tissues. 5. The results of this study support the view that platelet and vascular DP receptors are similar, assuming that the systematic difference in affinity estimates for the series of compounds between the two tissues is the consequence of receptor micro-environment and/or accessory binding site differences.
Full text
PDF







Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Black J. W., Leff P. Operational models of pharmacological agonism. Proc R Soc Lond B Biol Sci. 1983 Dec 22;220(1219):141–162. doi: 10.1098/rspb.1983.0093. [DOI] [PubMed] [Google Scholar]
- Black J. W., Leff P., Shankley N. P. Further analysis of anomalous pKB values for histamine H2-receptor antagonists on the mouse isolated stomach assay. Br J Pharmacol. 1985 Nov;86(3):581–587. doi: 10.1111/j.1476-5381.1985.tb08934.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dong Y. J., Jones R. L., Wilson N. H. Prostaglandin E receptor subtypes in smooth muscle: agonist activities of stable prostacyclin analogues. Br J Pharmacol. 1986 Jan;87(1):97–107. doi: 10.1111/j.1476-5381.1986.tb10161.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dukes M., Russell W., Walpole A. L. Potent luteolytic agents related to prostaglandin F2alpha. Nature. 1974 Jul 26;250(464):330–331. doi: 10.1038/250330a0. [DOI] [PubMed] [Google Scholar]
- Giles H., Leff P., Bolofo M. L., Kelly M. G., Robertson A. D. The classification of prostaglandin DP-receptors in platelets and vasculature using BW A868C, a novel, selective and potent competitive antagonist. Br J Pharmacol. 1989 Feb;96(2):291–300. doi: 10.1111/j.1476-5381.1989.tb11816.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jenkinson D. H. How we describe competitive antagonists: three questions of usage. Trends Pharmacol Sci. 1991 Feb;12(2):53–54. doi: 10.1016/0165-6147(91)90497-g. [DOI] [PubMed] [Google Scholar]
- Lawrence R. A., Jones R. L., Wilson N. H. Relaxant potencies of prostaglandin E analogues on rabbit jugular vein. Br J Pharmacol. 1989 Dec;98 (Suppl):796P–796P. [PubMed] [Google Scholar]
- Leff P., Martin G. R., Morse J. M. Differential classification of vascular smooth muscle and endothelial cell 5-HT receptors by use of tryptamine analogues. Br J Pharmacol. 1987 Jun;91(2):321–331. doi: 10.1111/j.1476-5381.1987.tb10287.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Leff P., Martin G. R., Morse J. M. The classification of peripheral 5-HT2-like receptors using tryptamine agonist and antagonist analogues. Br J Pharmacol. 1986 Nov;89(3):493–499. doi: 10.1111/j.1476-5381.1986.tb11149.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Leff P., Martin G. R. Peripheral 5-HT2-like receptors. Can they be classified with the available antagonists? Br J Pharmacol. 1986 Jul;88(3):585–593. doi: 10.1111/j.1476-5381.1986.tb10239.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Leff P., Prentice D. J., Giles H., Martin G. R., Wood J. Estimation of agonist affinity and efficacy by direct, operational model-fitting. J Pharmacol Methods. 1990 May;23(3):225–237. doi: 10.1016/0160-5402(90)90066-t. [DOI] [PubMed] [Google Scholar]
- Rang H. P. The kinetics of action of acetylcholine antagonists in smooth muscle. Proc R Soc Lond B Biol Sci. 1966 Apr 19;164(996):488–510. doi: 10.1098/rspb.1966.0045. [DOI] [PubMed] [Google Scholar]
- Town M. H., Casals-Stenzel J., Schillinger E. Pharmacological and cardiovascular properties of a hydantoin derivative, BW 245 C, with high affinity and selectivity for PGD2 receptors. Prostaglandins. 1983 Jan;25(1):13–28. doi: 10.1016/0090-6980(83)90131-4. [DOI] [PubMed] [Google Scholar]
- Whittle B. J., Moncada S., Mullane K., Vane J. R. Platelet and cardiovascular activity of the hydantoin BW245C, a potent prostaglandin analogue. Prostaglandins. 1983 Feb;25(2):205–223. doi: 10.1016/0090-6980(83)90105-3. [DOI] [PubMed] [Google Scholar]
