Histochemical distribution of phosphorylase in rodent brain from newborn to adults

Phosphorylase activity of the brain of rats from newborn to adults was investigated histochemically by Takeuchi and Kuriaki's method, using the iodine reaction. Additional studies were made of the brain of adult guinea pigs, mice and rabbits.

The phosphorylase of newborn rats was generally slight in activity, except for moderate or strong action in some structures: arachnoid membrane, choroid plexuses, ventricular walls, area postrema, pineal and subcommissural bodies, raphe of the medulla oblongata, some brain stem nuclei such as the nucleus of the mesencephalic tract and motor nucleus of the fifth nerve, nuclei of the facial and hypoglossal nerves. Slight reaction appeared in the ventral thalamic and habenular nuclei on the 3rd day, in the cerebral and cerebellar cortices and superior colliculus on the 5th day after birth. The enzyme activity showed a general increase at 14 days and reached the maximal intensity at about 21 days of age, while the arachnoid membrane, choroid plexuses amid raphe exhibited evident decrease of activity. The white matter showed an initial activity at different ages from 5 to 21 days, to attain maximal activity by 1 month.

In the adult a moderate purple staining was consistently demonstrated in the area postrema, subcommissural body and ventricular walls. The neopallium as well as the superior colliculus and cerebellar cortex showed strong or moderate brownish purple color. Nuclei of the brain stem gave characteristic staining; a purple color was encountered in the nucleus of the mesencephalic tract and motor nucleus of the fifth nerve, nuclei of the facial and hypoglossal nerves, brown or purplish brown color occurring in the caudate nucleus, putamen, interpeduncular and inferior olivary nuclei.

Histochemical studies of succinic dehydrogenase of the brain of mice, rats, guinea pigs and rabbits

Succinic dehydrogenase activity of the brain was histochemically investigated in mice, rats, guinea pigs and rabbits. Fresh frozen sections cut at 20 µ were stained with the Seligman-Rutenburg method as modified by Rosa and Velardo.

The pattern of enzyme distribution is remarkably similar but the intensity of staining differs somewhat in the animal species, being highest in mice and rats, intermediate in rabbits and lowest in guinea pigs. The enzyme activity is found exclusively in the grey matter and ocurs both in the perikaryon and neuropil. The activity in the grey matter exhibits the characteristic local variations which are ascribed to the varying participation of the nerve cell bodies and surrounding neuropils in the reaction. Nerve cell bodies contain variable amounts of dye particles of different sizes, and the neuropil possesses variable numbers of coarse granules. An intense reaction is given in the caudate nucleus, putamen, anterior nucleus of the thalamus, interpeduncular nucleus and cerebellar cortex. An intermediate activity occurs in the neocortex, rhinencephalon, optic tectum, most of the cranial nerve nuclei, superior and inferior olivary nuclei, and the Goll and Burdach nuclei. A low activity is present in the paraventricular structures, such as supraoptic crest, subfornical and subcommissural bodies, and area postrema, as well as the paraventricular and supraoptic nuclei of the hypothalamus, and dorsal nuclei of the vagus nerve.