Reactivity of pial vessels in response to a brain surface irrigation by norepinephrine solution in rats, subjected to transient global cerebral ischemia (2VO+hypo model), was investigated. Four different groups of rats at 2, 7, 14 or 21 days after ischemia were subjected to microvascular studies using in vivo video microscopy method. The diameter changes of pial arteries and veins in response to norepinephrine were measured. It was established that cerebral ischemia led to increase the number of the constrictions to norepinephrine mainly at the vessels to relating to a group of small pial arteries and arterioles and pial veins of the 3rd generation. Reactivity changes were observed in all time points studied. These changes probably is connected with caused by ischemia the increase in reactivity and sensitivity of pial vessels adrenoceptors. The greatest changes are noted in 14 days after ischemia.