Alterations of Brain Levels of Phosphoinositidase-C–Linked Gqα/G11α Proteins and Motor Function in Rats After Cardiac Arrest

Abstract

Background and Purpose Phosphoinositidase-C–linked G qα and G 11α proteins have only recently been characterized. Second messenger systems are known to be affected by hypoxia-ischemia. However, the effects of hypoxia-ischemia on the brain levels of G qα and G 11α proteins are not known. Therefore, in the present studies, the effects of hypoxia-ischemia on G qα and G 11α proteins in rats were investigated with quantitative immunoblot analysis. Methods Cardiac arrest was induced in male Sprague-Dawley rats by an intracardial injection of KCl. Resuscitation began 10 minutes afterwards. At various time points after resuscitation, animals were killed and the cerebral cortex, striatum, and cerebellum were dissected. Levels of G qα and G 11α proteins were investigated by quantitative immunoblot analysis. Results At 1, 2, 4, and 6 hours after resuscitation, G qα and G 11α protein levels remained unaltered. However, a significant reduction of these proteins was seen in the cerebral cortex and cerebellum of rats 3 and 14 days after cardiac arrest, with partial recovery by an average of 60 days. In contrast, no significant change was detected in the striatum. Conclusions These observations indicate that phosphoinositidase-C–linked signal transduction pathways may be attenuated after hypoxic-ischemic insults to the brain, and that this phenomenon, together with many other factors, may contribute to the expression of motor dysfunction in rats after cardiac arrest.