Cerebral blood flow and regional potassium distribution during focal ischemia of gerbil brain

Abstract

In 8 gerbils (Meriones unguiculatus) focal cerebral ischemia was produced by occlusion of the left common carotid artery and the opposite external carotid artery. After two hours blood flow was measured with iodoantipyrine labeled with carbon 14, and evaluated by means of quantitative autoradiography. Thereafter the same brain sections were stained for regional potassium by means of a histochemical technique. Changes in tissue potassium content were assessed by measuring the differences in optical densities in homotopic brain regions of the stained sections. The correlation between blood flow and tissue potassium level revealed that below a flow threshold of about 0.23 ml/gm/min, a definite potassium loss from the tissue was observed. The combination of autoradiographic methods with a technique for measuring the regional distribution of potassium may be useful in providing additional information on the occurrence of disturbed electrolyte homeostasis after the onset of focal ischemia.

Visualization of the ischemic core on native human brain slices by potassium staining method

“…Our results, regarding regional potassium distribution in lesioned and intact brain areas, are in line with the findings of Mies et al (1984). Potassium contents measured by flame atomic absorption spectrometry show significant differences between lesioned and intact brain regions which is evidently reflected by the pictorial representation of potassium distribution on whole hemisphere cryosections.…”

“…Whole hemisphere cryosections were treated by sodium cobaltnitrite which in the presence of potassium forms potassium cobaltnitrite, a brown-colored reaction product (Mies et al, 1984). Having performed the potassium staining the potassium "map" has been used as a "road-map" for identifying ischemic core and the rest of the native, intact brain tissue during targeted tissue sampling in the cryostat (Fig.…”

“…Animal models of stroke have demonstrated that after the acute ischemic insult, pictorial representation of potassium concentrations in the tissue correlates with hemodynamic and metabolic disturbances of ischemic brain tissue and it is a useful approach for evaluating the localization of regions in which ischemia has been sufficiently long and severe to jeopardize the structural integrity of the brain (Astrup et al, 1981;Jones et al, 2007;Mies et al, 1984;Price et al, 2003;Tobita et al, 1985;Young et al, 1987). It is also relevant that animal models of stroke are extremely heterogeneous.…”

“…It is also relevant that animal models of stroke are extremely heterogeneous. Mies et al (1984) showed in gerbil model of stroke, that the potassium staining correlates with the potassium content in the tissue and allows quantification of potassium changes.…”

Laser doppler flowmetry in CA1 sector of hippocampus and cortex after transient forebrain ischemia in gerbils.

“…717 In gerbils, in contrast, significant residual blood flow may persist after vascular occlusion. 18 " 20 This residual flow differs in different parts of the brain. After bilateral common carotid artery occlusion it amounted to 5.0±1.3 ml/100 g/min in the cortex and 8.0±2.7 ml/100 g/min in the hippocampus.…”