<Original Report>FACTORS LIMITING THE HISTOCHEMICAL REACTION OF CHOLINE DEHYDROGENASE ACTIVITY

Abstract

The histochemical reaction of choline dehydrogenase was completely inhibited by the pretreatment of cryostat sections with either absolute acetone or 10% water-in-acetone at room temperature (25℃). The temperature of the organic solvents was critical in the inhibition of the staining for choline dehydrogenase. As the temperature was lowered, the inhibitory effects of the pretreatment decreased. The staining lost by absolute acetone was restored by coenzyme Q_<10>, phenazine methosulfate, menadione, section-extracts and mitochondrial fraction extracts. On the other hand, the staining lost by 10% water-in-acetone was not restored. Both absolute acetone and 10% water-in-acetone produced the same inhibitory effect upon the staining. There was, however, a difference between the effect of absolute acetone and that of 10% water-in-acetone in the restoration of the staining lost by the pretreatment of the sections. Coenzyme Q_<10> and phospholipids are suggested as limiting factors in the histochemical reaction of choline dehydrogenase.