Endothelin and transient cerebral ischemia: An immunohistochemical study in the Mongolian gerbil

The distribution of endothelin has been investigated by immunohistochemical techniques in the nervous tissue of Mongolian gerbils in which transient unilateral forebrain ischemia was provoked by occlusion of the common carotid artery of one side for different intervals (30 min to 4 h). Computer-assisted densitometric analysis showed that the intensity of immunostaining was higher in the hemisphere ipsilateral to the carotid occlusion. The greatest differences were observed in the striatum, in the thalamus and, for the longest occlusions, in the cerebral cortex. Different degrees of asymmetry, observed between animals, are likely dependent on the duration of carotid occlusion and/or on a variable residual blood flow from the contralateral hemisphere. It is suggested that cerebral ischemia is paralleled by an increased tissue concentration of endothelin which, due to its potent vasoconstrictive effect, might further worsen tissue perfusion.