Regional Cerebral Glucose Metabolism and Blood Flow During the Silent Phase of Methylmercury Neurotoxicity in Rats

Methylmercuric chloride was given to rats in a neurotoxic dose regimen (six daily doses of 8 mg kg-1 p.o.). During the silent (asymptomatic) phase of intoxication, the rates of cerebral glucose influx and cerebral glucose phosphorylation were measured simultaneously using 2-deoxyglucose. Regional cerebral blood flow was also measured using iodoantipyrine. The unidirectional flux of glucose into brain was not affected by methylmercury, and differences in the rates of glucose phosphorylation from region to region remained coupled to the regional cerebral blood flow. However, the blood flow was reduced throughout the brain, an observation suggesting that the operational level of metabolically regulated blood flow had been reset. Thus, in spite of a generalised reduction in blood flow, there was no indication of impaired cerebral glucose supply or utilization during the silent phase of methylmercury intoxication.