Regional distribution of choline acetyltransferase and acetylcholinesterase activity in baboon brain.

(1) The activities of choline acetyltransferase (ChAc) (EC 2.3.1.6) and acetylcholinesterase (AChE) (EC 3.1.1.7) were determined in about one hundred regions and subregions of baboon brain. The activities and distributions of these enzymes were in comparable to those found previously in the brains of other species. (2) ChAc activity was highest in the interpeduncular nucleus, where it was about twice that in the putamen, the region previously thought to be the richest in this enzyme. The caudate nucleus, the substantia perforata, the nucleus basalis, the central part of the amygdala and the oculomotor nucleus also had high activities. The activities in the cerebral and cerebellar cortex were less than one twentieth of that in the interpeduncular nucleus. (3) The distribution of AChE activity was not entirely in parallel with that of ChAc.