Effects of Transient Global Cerebral Ischemia on Peptide Neuronal Populations in Different Brain Regions and on Behavioral Performances in Rats

It is known that neurons are more sensitive to ischemic damage than oligodendroglia, astroglia, and endothelial cells [7]. Furthermore, the neuronal populations in various brain regions show a differential vulnerability to ischemia [2, 13]. The mechanism underlying the regional vulnerability of nerve cell populations to global ischemia is still unknown and does not seem to be simply related to the degree of vascularization, energy requirements, and chemical coding [11]. In previous papers on the aging processes it was shown that various peptide neuronal systems show a marked reduction in the aged rat brain [see, e.g., 1, 15]. In the present study using semiquantitative immunocytochemistry we have therefore studied how neocortical, hippocampal, and hypothalamic neuropeptide-containing neurons respond to global ischemia induced by the Pulsinelli model [12]. The analysis also involves studies on the time course of the recovery of peptide immunoreactivities during reperfusion. This time course was related to the learning deficit induced by the brain ischemia as evaluated by a T-maze test.