TIME-DEPENDENT EFFECTS OF ACUTE ETHANOL ADMINISTRATION ON REGIONAL CEREBRAL BLOOD-FLOW IN THE RAT

The present study investigated the role of the postinjection interval in determining the functional consequences of acute ethanol administra tion in the CNS. Regional cerebral blood now (RCBF) was determined by the [C-14]iodoantipyrine method in 33 brain structures of ethanol-naiv e Sprague-Dawley rats. In the first experiment, changes in RCBF were a ssessed 5 and 15 min after a 0.8 g/kg (IP) dose of ethanol or water. F ive minutes after treatment, rates of RCBF were increased in the motor cortex, agranular insular cortex, and the olfactory tubercle compared to water controls. No significant differences compared to control wer e found at the 15-min time point, despite the continued presence of et hanol in the blood. Experiment 2 tested whether blood ethanol level wa s the sole determinant of this response to ethanol by comparing animal s with the same blood ethanol level at the 5- and 15-min time points. Greater rates of RCBF were found at 5 min postinjection compared to 15 min, in the motor cortex, agranular insular cortex, caudate/putamen, cerebellum, and the lateral septum. These data demonstrate that the ra tes of cerebral blood flow are increased in regionally discrete portio ns of the rat brain shortly after ethanol administration. Furthermore, blood ethanol level is not the exclusive factor governing this functi onal response. (C) 1998 Elsevier Science Inc.