Enzyme-histochemical studies on the nonsecretory neurons of the rat supraoptic nucleus with the application of karyometry and electronmicroscopy.
Detailed histochemical studies were conducted on the distribution of SDH, G6PD, and TPPase as well as the Nissl substance and Gomori-positive material in the nonsecretory neurons of the supraoptic nucleus (SO) of the adult Wistar strain rats. Karyometry and statistical analysis were performed to identify those neurons. Electron microscopy confirmed the cytological characteristics indicated by the histochemical results. Based on the classification of SO neurons by the Golgi-Cox method and the present results concerning the Nissl pattern, shape, size, and number, these nonsecretory neurons appear to be intercalated neurons. Weak SDH and G6PD activity in the perikaryon with a few mitochondria indicate that they belong to the category of ordinary neurons with a low level of carbohydrate metabolism. The TPPase reaction revealed heterogeneous Golgi apparatus (GA) with poor development. In addition, it was difficult to find profiles of GA in many ultrathin sections. These results indicate that the GA may not undergo cyclic activity and lacks the capacity for secretion. No Gomori-positive material was detected in the perikaryon, whereas the Nissl substance was densely distributed throughout the entire perikaryon, where many free ribosomal rosettes and junctions of cisternae of abundant granular reticulum were evenly dispersed. The nonsecretory neurons reflect an active phase of cyclic activity of protein synthesis. However, other nonsecretory neurons with less active protein synthesis are very likely to be present.
D000818:Animals; D005260:Female; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D006651:Histocytochemistry; D007620:Karyometry; D008854:Microscopy, Electron; D009474:Neurons / Q000201:enzymology; D051381:Rats; D013385:Succinate Dehydrogenase / Q000378:metabolism; D013495:Supraoptic Nucleus / Q000201:enzymology* / Q000648:ultrastructure; D013834:Thiamine Pyrophosphatase / Q000378:metabolism
D005954:Glucosephosphate Dehydrogenase; D013385:Succinate Dehydrogenase; D013834:Thiamine Pyrophosphatase