Certain cells in the hypothalamic neurosecretory nuclei which are stainable by the acid-haematein test for phospholipids according to Baker

Summary

This paper presents a description of ganglion cells in the neurosecretory nuclei (s.o.n. and p.v.n.), which stain positively by the Baker technique for demonstration of phospholipids. These cells differ from the other cells in these nuclei, which have a more rounded shape and remain completely unstained. Even with iron-haematoxylin these cells are demonstrable. In a study of serial sections these black-staining elements were identified as ganglion cells, not astrocytes. Moreover the Baker-staining cells are possibly identical with the ganglion cells staining homogeneously dark with aldehyde-fuchsin, and often showing a spindle shape and a pyknotic nucleus. In addition to the cells themselves, their processes also stain by the Baker technique. These myelinated processes can often be followed over a considerable distance, passing as they do between the non-staining ganglion cells without forming synaptic junctions.

The question is raised whether these Baker-positive cells are ganglion cells which have a separate function in the neurosecretory nuclei, or whether they are lipid-loaded cells which must be regarded as a stage in the cycle of neurosecretion.

Apart from the neurosecretory nuclei, it is possible by these staining techniques to demonstrate that throughout the CNS positively staining ganglion cells with their processes occur alongside non-staining ganglion cells. Examples of this were found in the cerebral cortex, the cerebellar cortex, in which the Purkinje cells with their most delicate processes stain, and the cortex of the hippocampus.

In slides of the hypothalamus fixed according to Pfuhl, the large neurosecretory ganglion cells frequently contain granules or droplets which stain red with aldehyde-fuchsin, and granules forming the pearl-strings outside the neurosecretory nuclei. These granules, however, cannot be stained with iron-haematoxylin or by the Baker technique.

The ganglion cells discussed in this paper stain well with iron-haematoxylin in these Pfuhl-fixed specimens. This indicates a difference between the substance in the granules in the large, round neurosecretion-forming ganglion cells and the pearl-strings, and that in the dark staining cells. Our conclusion is that the neurosecretory nuclei contain two different types of cells.

We do not share the view that the Bakerpositive cells are merely shrinking artefacts in the sense used by Scharrer and Cammermeyer.