Changes of neuropeptides and their receptors in experimental stroke gerbil brains

Eight kinds of neuropeptides and four kinds of neuropeptide receptors were examined in the right and left hemispheres of mongolian gerbils after unilateral carotid ligation-induced stroke and in normal controls. Five hours after ligation of the right common carotid artery, β-endorphin concentration in the right hemisphere (ischemic side) of the stroke group was significantly increased compared with that in the contralateral hemisphere (non-ischemic side), but there were no differences between sides in other neuropeptides either with or without stroke. Furthermore, although there were no differences in [³H]naloxone binding, [³H]thyrotropin-releasing hormone binding or ¹²⁵I-vasoactive intestinal polypeptide binding in the brain in this model of stroke, [³H]enkephalin binding was significantly lower on the ischemic side than on the non-ischemic side in the stroke group. These results suggest that increased activity in the β-endorphinergic system in the brain might be partly caused by ischemic brain failure.