Comparative Study of the Histoenzymological Properties of the Supraoptic and Paraventricular Nuclei and of Other Nuclear Regions of the Hypothalamus, the Epithalamus-Epiphysis Region and the Subfornical Organ

Abstract

In the hypothalamus of white rats ganglion cell groups can be observed which show enzyme histochemical properties (low SDH and CYO, moderate G₆PDH and TPND and marked LDH and MDH activity) similar to those of the supraoptic and paraventricular nuclei performing secretory function. These cell groups are the accessory magnocellular cell groups, those radiating from the paraventricular nucleus, all the cells of the nucleus tuberomamillaris as well as cells located in the area of the nucleus periventricularis arcuatus, cells situated inframamillarily and arranged peri- and parafornically in the infundibular plane. From the histoenzymological point of view several similar traits can be observed between these cell groups and the epiphysis as well as the special ependymal parts or organs of the third ventricle. On the basis of analogy it is conceivable that also the said cell groups of the hypothalamus perform secretory function.

Data on the Enzyme Histochemistry of the Ependyma Lining the Infundibular and Inframammillary Recesses of the Third Cerebral Ventricle, with Special Regard to the Connexions of the Tanycytes

“…As regards the functional morphological connexions, reference is made to the review of Leonhardt [14], In our experience, the oxidative enzyme structure of the tanycyte ependyma, the subfornical and subcommissural organs, which presumably exert secretory activity, and the various hypothalamic peptider gic neurones are similar in many respects (low SDH andCYO, and significant LDH. GbPD and TPND activities) [2], There is an essential difference, however, that the tanycyte ependyma does not possess TPPase activitylocalised [18,22] on the cisterns of the Golgi apparatus and important in protein synthesis nor acid phosphatase activity [24], which are character istic for the others. According to the autoradiographic observations of F ujita [8], the ependymal cells of an adult mouse do not exhibit a tendency to protein secretion.…”

“…We reported in our earlier papers [1,2] on the more significant GfiPD, TPDN, and TPPase activities of the top of the inframammillary recess compared to the ciliated ependyma elsewhere lining the third ventricle. Colmant [4] has demonstrated that the activity of TPND is locally stronger on the dorsal part of the third ventricle.…”

“…TPNdiaphorase. and lactic acid dehydrogenase reactions, which outline the processes beside the cell body; also the intense ATPase activity chiefly in the middle zone, and considerable aliesterase activity nearly everywhere [4,24], In our earlier examinations of the histoenzymological properties of the hypo thalamic nuclei, the epithalamus-epiphysis system and subfornical organ, we also observed different reactions of the ependyma lining the third ventricle [1,2], It is believed that the distal processes of the tanycytes penetrate into the parvicellular hypothalamic nuclei, and -crossing the infundibulum caudallyterminate on the capillaries of the portal plexus together with the neurones of these nuclei. On the basis of the inframammillary recess and according to the proximal adenoneurohypophyseal contact surface, they reach the outer surface of the brain.…”