Activities of alkaline phosphatase and Na+-K+-adenosine 5'-triphosphatase in the brain of experimentally produced histidinaemic squirrels (Funambulus palmarum)

In the two areas of the brain examined (olfactory lobes and cerebral hemispheres) the activity of alkaline phosphatase was lower in squirrels that had received injections of l-histidine for 4 days; the degree of inhibition of the enzyme was greater when the histidinaemia was more severe. A much smaller reduction was found in the activity of Na⁺-K⁺-adenosine 5′-triphosphatase. The possibility that these effects of histidinaemia might be related to the changes in the transport of substances into the brain that occur in this syndrome was discussed.