Cholinesterase in cerebrospinal fluid

1. 1. Butyrylcholine is a specific substrate for pseudo-cholinesterase, and may be used as such for the determination of the pseudo-cholinesterase activity of c.s.f. It is hydrolysed at a faster rate than benzoylcholine. 2. 2. Butyrylcholine is an inhibitor of true-cholinesterase. 3. 3. Individual c.s.f.s of human patients hydrolyse acetylcholine, butyrylcholine and acetyl-β-methylcholine and sometimes tributyrine. 4. 4. Pooled c.s.f.'s from a number of human patients hydrolyse acetylcholine, acetyl-β-methylcholine, benzoylcholine, propionylcholine, Butyrylcholine, triacetine, tributyrine and sometimes monobutyrine. No hydrolysis of ethyl- or methylbutyrate could be demonstrated. 5. 5. The weak cholinesterase-activity of c.s.f. may be enhanced by evaporation. The increase of activity per ml by this procedure is less than would be predicted from the degree of concentration. It moreover differs with the substrates used. 6. 6. Tributyrine hydrolysis may be inhibited by eserine, but only in concentrations which are at least 1000 times stronger than those, necessary for the complete inhibition of acetylcholine hydrolysis. 7. 7. It is concluded that c.s.f. containes pseudo- as well as true-cholinesterase. Sometimes lipase is present. Ali-esterase does not occur in c.s.f.