Role of striatal glutamate in heatstroke-induced damage in streptozotocin-induced diabetic rats

In heatstroke related symptoms in streptozotocin-induced diabetic rats (STZ-diabetic rats) exposed to a high temperature (43 degreesC) for 60 min. like that in normal rats, the high colon temperature and the decreases of mean arterial pressure, heart rate and cerebral blood flow were abolished by MK-801. the NMDA receptor antagonist. Also, striatal glutamate was markedly released in both animals by this exposure while the release was higher and the survival time was shorter in STZ-diabetic rats than in normal rats. After insulin treatment, like that by MK-801 pretreatment. the striatal glutamate and the incidence of heatstroke in STZ-diabetic rats were markedly reduced. Therefore, heatstroke was more easily induced via the elevated striatal glutamate in STZ-diabetic rats by high temperature exposure. Insulin treatment seems helpful in the prevention of heatstroke in STZ-diabetic rats. (C) 2003 Elsevier Ireland Ltd. All rights reserved.