Pharmacological profile of UK-74,505, a novel and selective PAF antagonist with potent and prolonged oral activity
| Autor: | M J, Parry, V A, Alabaster, H E, Cheeseman, K, Cooper, R N, deSouza, R F, Keir |
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| Rok vydání: | 1994 |
| Předmět: |
Blood Platelets
Male Dihydropyridines Calcium Channels L-Type Platelet Aggregation Guinea Pigs Administration Oral Muscle Proteins Mice Inbred Strains In Vitro Techniques Tritium Potassium Chloride Capillary Permeability Rats Sprague-Dawley Diltiazem Mice Animals Gallopamil Platelet Activating Factor Aorta Skin Membranes Nitrendipine Imidazoles Brain Azepines Triazoles Rats Kinetics Cattle Rabbits Hypotension Platelet Aggregation Inhibitors Muscle Contraction |
| Zdroj: | Journal of lipid mediators and cell signalling. 10(3) |
| ISSN: | 0929-7855 |
| Popis: | UK-74505, a novel 1,4-dihydropyridine PAF antagonist, exhibited highly selective, time-dependent inhibition of PAF-induced aggregation of rabbit washed platelets (IC50 = 26.3 +/- 0.88 and 1.12 +/- 0.04 nM after 0.25 and 60 min preincubation, respectively), which became irreversible within 15 min, whereas inhibition by WEB-2086 was both independent of preincubation time (IC50 = 145.7 +/- 24.7 nM) and competitive (KI = 27.5 +/- 7.7 nM; Schild slope = 0.98 +/- 0.04). The selective inhibition of specific [3H]PAF binding by UK-74,505 exhibited a slower onset, the IC50 obtained without preincubation (14.7 +/- 2.6 nM) decreasing 2-fold at 45 min. UK-74,505 was 450-fold weaker as an antagonist of [3H]nitrendipine binding to bovine brain membranes and KCl-induced contraction of rat aorta. UK-74,505 was 10-30-fold more potent than WEB-2086 in vivo as an inhibitor of PAF-induced hypotension in rats (ED50 = 35 +/- 5.8 micrograms/kg, i.v.), cutaneous vascular permeability in guinea pigs (ED50 = 0.37 +/- 0.08 mg/kg, p.o.) and lethality in mice, with oral ED50 values of 0.26 +/- 0.03 and 1.33 +/- 0.19 mg/kg at 2 and 8 h, respectively. These data demonstrate that UK-74,505 is a potent, selective, long-acting irreversible PAF antagonist. |
| Databáze: | OpenAIRE |
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