抄録
The author has histochemically studied the alteration of cholinesterase of the brain of rats from late fetal life to adult. The results were as followed.
1. The periods of time necessary to attain maximal enzyme activities varied: the medulla oblongata and midbrain attained their maximal reaction at 14 days of age, diencephalone and nuclei cerebri at 21 days of age, while cerebral cortex in the age of 3 months.
2. In the medulla oblongata, the nucleus ambiguus gave marked activity in the late fetal life followed by the maximal reaction at 5 days of age. The nucleus of the hypoglossal nerve and dorsal motor nucleus of vagus nerve showed the similar changes.
3. In the pons, the earliest and marked activity was demonstrated in the locus caeruleus, while moderate reaction appeared in the motor and mesencephalic nuclei of the fifth nerve from newborn animals.
4. The midbrain showed an initial activity at varying ages. For examples, nucleus of 3rd nerve and mesencephalic nucleus of the fifth nerve in 20th days of fetal age, nucleus interpeduncularis in the newborn animals, colliculus rostralis at 10 days of age. The activity of the nucleus of 3rd nerve was followed by rapid increase from 2 weeks of age.
5. The evident activity was demonstrated in the corpus LUYSI, fasciculus retroflexus and habenular nucleus in newborn animals. The ventral thalamic nucleus was the first reacting nucleus in the thalamus, to reach the moderate staining by 3 days of age.
6. A slight activity made its appearance in the striatum by 10 days of age, followed by gradual increase to attain maximal activity at 21 days of age.
