Histamine Release, an Undesired Effect of Thrombin Inhibitors with Basic Character, is Mediated Through Direct Activation of G(I) Proteins.
From: Department of Pharmacology and Experimental Toxicology, Faculty of Medicine, University of Ljubljana, Korytkova 2, 1000 Ljubljana, Slovenia. mateja.stempelj@mf.uni-lj.si
European journal of pharmacology
- Publish Date: May 2006
- ISSN: 0014-2999
- Volume: 538
- Issue: 1-3
- Pages: 182-7
- Medium: Print
- Language: English
- Citation (JAMA): Stempelj Mateja, Zorko Matjaz, Peternel Luka, et al. Histamine Release, an Undesired Effect of Thrombin Inhibitors with Basic Character, is Mediated Through Direct Activation of G(I) Proteins.. Eur. J. Pharmacol. May 2006;538:182-7
Abstract
The common structural feature of LK direct thrombin inhibitors is a strong basic group attached to the azaphenylalanine scaffold, which is important for the appropriate interaction at the thrombin active site. Our previous results have shown that this basic group could be responsible for a reduction of tracheal air flow and a fall of mean arterial pressure in anaesthetized rats, an undesired effect of direct thrombin inhibitors which correlated with their ability to release histamine from mast cells. In the present study, we investigated the mechanism of LK direct thrombin inhibitors-induced histamine release from rat peritoneal mast cells. We demonstrated that thrombin inhibitors with basic character (LK-732, LK-639 and LK-6063) provoked release of histamine from mast cells, while less basic analogs (LK-658, LK-633 and LK-6062) had no effect. Histamine released by LK-732 and LK-639 was suppressed by removal of sialic acid residues by neuraminidase and by pertussis toxin, an inhibitor of G(i) protein activity. Additional demonstration that G proteins are the targets of LK-732 and LK-639 was provided by the increase of GTPgammaS binding rate to G proteins in rat brain cortical membranes. Our results indicate that basic direct thrombin inhibitors LK-732 and LK-639 provoke release of histamine from mast cells by direct activation of G(i) proteins through the similar biochemical pathway as basic secretagogues.
Mesh Headings (Keywords): Analysis of Variance, Aniline Compounds, Animals, Cell Survival, Cells, Cultured, Dose-Response Relationship, Drug, GTP-Binding Protein alpha Subunits, Gi-Go, Guanosine 5’-O-(3-Thiotriphosphate), Histamine, Histamine Release, Male, Mast Cells, Naphthalenes, Pertussis Toxin, Phenylalanine, Protein Binding, Rats, Rats, Wistar, Structure-Activity Relationship, Thrombin
Check for Full Text / PubMed Unique Identifier (PMID): 16650405
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