Determination of the Cholinesterase Activity in Blood and Organs by Automatic Titration. With some Observations on Serious Errors of the Method and Remarks of the Photometric Determination.

Cholinesterase Activity in Plasma and Erythrocytes

“…Measurement of cholinesterase activity is based on the result of a semiautomatic titration with NaOH (0.02 N) of the acetic acid produced by adding acetylcholine chloride (100 mg) to 1 ml of plasma or erythrocyte concentrate at fixed pH (7.4), fixed temperature (38' C), and in fixed environment (0.90/0 NaCl) (9). W e have paid no attention to differences in the two enzymes: the erythrocyte acetylcholinesterase and the plasma cholinesterase (pseudocholinesterase).…”

“…Several methods have been employed for estimating the cholinesterase activity. The most frequent are the colorimetric (6) and the acidimetric methods, the latter employed either manometrically (l), by measuring the A pH (18), or by continuous titration (9,11,20). For theoretical and practical reasons this latter procedure must to-day be regarded as the best one, the titration taking place at a constant pH and temperature in .physiological environment<<.…”

The Lethal Action of Morphine and Nalorphine given jointly to Morphine Tolerant and Non‐Tolerant Rats

“…Thc demonstrated increased tolerance to the lethal and convulsant action of morphine and nalorphine must therefore be connected with the fact that the morphine tolerant rats have developed a tolerance to nalorphine that makes it possible for them to survive higher concentrations of nalorphine in the brain. JOHANNESSON ( 1962) found that morphine inhibits brain cholinesterase activity to the same extent in morphine tolerant and non-tolerant rats. In our investigation morphine and nalorphine also inhibited cholinesterase activity to about the same extent in homogenates of brains from tolerant and non-tolerant rats, and cholinesterase activity has been found to be the same in homogenates of brain from tolerant and non-tolerant rats (JOHANNESSON 1962).…”

“…When morphinechloride, nalorphinechloride, or normorphinechloride was used as inhibitor, the homogenate of the whole brain was incubated for 10 minutes before adding the substrate, and the activities were then determined and expressed as percentages of the control values (for details, see JOHANNESSON & LAUSEN 1961).…”