Increased histamine release and granulocytes within the thalamus of a rat model of Wernicke's encephalopathy

The current study examined the possible role of increased histamine release and granulocyte activity in the vascular changes chat precede the onset of necrotic lesions with the thalamus of the pyrithiamine-induced thiamine de ficiency (PTD) rat model of Wernicke's encephalopathy (WE). An increase in histamine release and the number of granulocytes was observed in lateral th alamus on day 9 and in medial thalamus on day 10 of PTD treatment, a durati on of thiamine deficiency associated with perivascular edema in this brain region. Within the hippocampus, histamine release was significantly increas ed on day 9, declined to control levels on days 10-12, and was significantl y elevated on days 12-14. No granulocytes were observed in hippocampus of e ither PTD or control rats. These observations suggest that the release of h istamine from nerve terminals and histamine and other vasoactive substances from granulocytes may be responsible for thiamine deficiency-induced vascu lar breakdown and perivascular edema within thalamus. (C) 2000 Elsevier Sci ence B.V. All rights reserved.