Coronary vascular endothelium-myocyte interactions in protection of the heart by ischaemic preconditioning

Because ischaemia preconditioning is a general phenomenon - it is present i n almost all tissues and organs - we must look for a mechanism which involv es cell types common to all organs. The hypothesis outlined below is that e ndothelial cells, in response to a brief ischaemic stimulus, release protec tive mediators which (in the heart) diffuse to cardiac myocytes to increase resistance to a subsequent ischaemic stress. These substances include nitr ic oxide, generated through initial bradykinin release, and prostacyclin. T he evidence includes measurement of mediator release and the pharmacologica l attenuation of the antiarrythmic effects of preconditioning by blockade o f bradykinin receptors and inhibition of:nitric oxide production.