Ethanol in preweanling rats with dams: body temperature unaffected.

At an ambient temperature of 24 degrees C, the neonatal rat was found to exhibit poikilothermic characteristics if separated from the dam. On day one after birth, at one hour after separation from dams, the body temperature in rat pups was found to be identical with ambient temperature. Preweanling pups, under these circumstances, were unable to maintain a constant body temperature prior to day 19 postnatally. No differences were observed in body temperatures of rat pups treated chronically (days 6-16 postnatally) with ethanol 4 g/kg body weight (in two 2 g/kg doses three hours apart), as compared with isocaloric isovolumetric milk-, or sham-treated control groups. A significantly lower temperature was observed only at 105 minutes after the first treatment in a group of rats acutely treated (one day only) with ethanol on day 22 postnatally as compared with an isovolumetric water control group. In adult rats, also treated acutely with ethanol, a significant hypothermic response occurred at 105 minutes after the first 2 g/kg dose and persisted during the remainder of the observation period. This study shows that body temperature was unaffected in neonatal Sprague-Dawley rats left with their dams after intubation with ethanol 4 g/kg body weight. Therefore any brain biochemical and/or structural alterations resulting from ethanol exposure, using this animal model, are not due to an ethanol induced hypothermic response.

Blood-brain barrier, aging, brain blood flow, and sleep.

We have shown that significant ultrastructural changes occur with increasing age in the BBB in the nonhuman primate. It is probable that similar changes occur in aging humans. Clearly, morphophysiological changes, i.e., structural changes in cerebral capillaries, may alter the BBB mechanism as well as capillary perfusion which, in turn, may affect cerebral energy metabolism and neuronal function. Thus neurological function may be affected and sensitive indices of function such as sleep patterns altered.

Changes with age in cerebral capillary morphology.

Age related alterations in cerebral capillary morphology were investigated in 4-, 10-, and 20-year-old Macaque monkeys and in 1-, 14-, 35-, 180-, and 800-day-old Sprague-Dawley rats. This study revealed the following changes with increasing age: a significant decrease in cerebral capillary wall thickness in frontal cortex in monkeys but not in rats; a significant increase in the thickness of basal lamina (BL) of cerebral capillaries in rats but not in monkeys, however there was a marked increase in this parameter in the monkey between 4 and 10 years of age; a significant decline in cerebral capillary endothelial mitochondrial content in monkeys whereas a significant decline in this parameter in rats was found only when the peak content at 35 days was contrasted with that at 800 days of age; and, aberrant tight junctions and thickened BL in one of five 20-year-old monkeys. These findings suggest impairment of barrier characteristics of cerebral capillaries with increasing age in both the rat and the monkey.