Session 21 : Pharmacologie cardiovasculaire, Endothelium et oxide nitrique

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Session 21 : Pharmacologie cardiovasculaire, Endothelium et oxide nitrique

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LOW DOSE OF BACTERIAL ENDOTOXIN INCREASES ENDOTHELIUM-DEPENDENT RELAXATION OF RAT ISOLATED AORTA

Q. Pu, R. Bordet, D. Deplanque, F. Puisieux, B. Vallet, B. Dupuis

Laboratoire de Pharmacologie, Faculté de Médecine, 1 place de Verdun, 59045 Lille Cedex, France

Bacterial endotoxin, administered in low doses induces ischemic tolerance in myocardium as well as in brain. Recently it has been suggested that heat stress, another procedure of ischemic tolerance, increased endothelium-dependent relaxations of rat isolated arteries, contributing to its anti-ischemic properties. We have investigated effect a low dose of bacterial endotoxin on endothelium-dependent relaxation of rat isolated aorta.

Bacterial endotoxin (lipopolysaccharide derived from Escherichia coli) was injected intraperitoneally in conscious rats (n=6) in a dose of 0.5 mg.kg-1. Control animals (n=6) received saline solution. Twenty four hours later, segments of rat aorta were isolated and mounted in organ chambers to analyse contraction induced by phenylephrine and relaxing response (E) to acetylcholine (Ach), calcium inophore A 23 187 and sodium nitroprusside (SNP).

Bacterial endotoxin increased significantly (p