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RESEARCH PRODUCT
Clonidine increases membrane-associated phospholipase A2
C. KonradJ. SchmeckMarcus SchleyU. S. R. HelfrichGeorg Petroianusubject
Blood PlateletsMalemedicine.medical_specialtyAnti-Inflammatory AgentsInflammationIn Vitro TechniquesClonidinePhospholipases AInternal medicinemedicineHumansPlateletchemistry.chemical_classificationPhospholipase Abusiness.industryGroup IV Phospholipases A2Cell MembraneSubstrate (chemistry)Lipid signalingClonidinePhospholipases A2Anesthesiology and Pain MedicineEndocrinologyEnzymeMembranechemistryFemalemedicine.symptombusinessAdrenergic alpha-AgonistsAdjuvants Anesthesiamedicine.drugdescription
Background and objective: An anti-inflammatory effect of α 2 -adrenoreceptor agonists has been suggested. Phospholipase A 2 is a key enzyme in the production of precursors of inflammatory lipid mediators. The aim of the present study was to investigate the effect of clonidine on phospholipase A 2 activity in an established in vitro model. Methods: Human being platelet membranes containing active phospholipase A 2 were exposed to buffer control or to three increasing concentrations of clonidine. Phospholipase A 2 was measured by a radioisotope technique. Results: A massive increase in phospholipase A 2 activity was measured after clonidine exposure leading to final values of 92.5 ′ 3.1 pmol mg protein - 1 min - 1 (4.5-fold higher than control values; P ≤ 0.01 vs. control). After clonidine exposure the maximal reaction velocity increased, while the Michaelis-Menten constant did not change. The Lineweaver-Burk representation suggested an interaction of clonidine with the phospholipase A 2 -substrate complex as well as the phospholipase A 2 molecule. Conclusion: We conclude that the putative anti-inflammatory effect of clonidine was not caused by inhibition of phospholipase A 2 .
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2005-12-01 | European Journal of Anaesthesiology |