Role of α2-adrenoceptors in brain resistance to total ischemiaadrenoceptors in brain resistance to total ischemia

Abstract

Neuroprotective effect of epinephrine is revealed against the background of pmzosin, 13antagonists and their combinations protect against cerebral ischemia, c~2-Antagonists (but not 0~) block the neuroprotective effect of these combinations, methyldopa, guanabenz, clonidine, and oxymetazoline and decrease brain resistance to ischemia, a2-Adrenocept015 participate in the endogenic mechanism of brain resistance to ischemia and in the neuroprotective effect.Epinephrine does not change the resistance of brain to total cerebral ischemia (CI), although its effect is manifested against the background of propranolol [1]. Shnilar effects of other adrenoceptor antagonists were not studied, c~2-Agonists produce a marked neuroprotective effect (NPE), i.e., the cerebral protective effect, which was demonstrated in various models of CI [1,2,[6][7][8]. It is generally accepted that to prove the role of cm~ain receptors in any physiological effect means to use blockade analysis. NPE of clonidine [1] and dexmedetomidine [6] is blocked by ~2antagonists. The respective data are still absent for agonists of dihydroxyphenylethanolamine and aminoguanidine groups. Moreover, idazoxan, an efficient blocker of (z2-receptors , protects the brain against CI [5,8]. The aim of the present study was to elucidate the role of 0~2-adrenoceptors in resistance to total CI with the help of the blockade analysis.