Brain, Vol. 109, No. 4, 771-784, 1986
© 1986 Guarantors of Brain
research-article |
REGIONAL CEREBRAL BLOOD FLOW IN AWAKE BEAGLES OF DIFFERENT AGES
Laboratory of Neurosciences, National Institute on Aging, National Institutes of Health, Bethesda, Maryland, and Animal Resource Facility, Gerontology Research Center, National Institute on Aging, Baltimore City Hospitals Baltimore, Maryland, USA
Correspondence to:
Correspondence to Dr Stanley I Rapoport, Laboratory of Neurosciences, National Institute on Aging, National Institutes of Health, Bethesda, Maryland 20892, USA.
SUMMARY
Regional cerebral blood flow (rCBF) was measured in 35 brain regions of awake beagles of different ages, by infusing 14C-iodoantipyrine intravenously. Between 13 and 612 yrs of age, rCBF was reduced significantly (P<0.01) in only 6 of the 35 regions, by 16 to 25%, and mean weighted CBF was not significantly altered. At 1415 yrs, rCBF was reduced significantly by 25 to 50% in 13 of 28 grey matter regions examined, but in no white matter region, as compared with rCBF at 13 yrs of age, and mean weighted CBF was reduced by 30% (P<0.01) The course of rCBF during ageing of the beagle corresponded to the reported course of the regional cerebral metabolic rate for glucose. The results demonstrate that cerebral functional activity in most brain regions is constant during much of the adult life of the beagle, and that coupling between blood flow and metabolism also is constant. Compensatory morphological and neurochemical mechanisms may account for this homeostasis of CBF. In extreme senescence, generalized reductions in rCBF are found, and probably reflect reduced sensory input to the brain as well as systemic disease.
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Received March 29, 1985. Revised September 26, 1985. Accepted December 12, 1985.
1Present address: Department of Neurosurgery, Tokyo Medical and Dental University Tokyo, Japan