ISSN:
1432-0878
Keywords:
Paraventricular nucleus
;
Rat
;
Synthesis of hormones
;
Acid phosphatase
;
Osmium impregnation
;
Neurosecretion
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary The ultrastructural features of the paraventricular neurones of the non-treated rat are presented comparing them with those of the supraoptic neurones. No striking differences are seen between the general electron microscopic characteristics of the paraventricular and supraoptic neurones. The importance of adequate fixation to obtain good preservation of the neurones is emphasized, since inadequate fixation can cause e.g. artefactual appearance of “dark neurones”. The previously presented classification of the neurosecretory neurones into two categories (e.g. “light and dark neurones”) on the basis of the number of ribosomes is not considered justifiable, since their number can vary to a very great extent even within a single cell. The synthesis of neurosecretory products in the paraventricular neurones obviously follows the general mode of the synthesis of secretory proteins: ribosomes—RER—Golgi complex—secretory vesicles. On the basis of the localization of heavy metal deposits after osmium impregnation and demonstration of acid phosphatase the Golgi complex of the paraventricular neurones is found to be polarized. The direction of the polarity is discussed. The substructures of the dense cores of the neurosecretory granules and of the contents of the lysosomal dense bodies are nearly identical. Therefore it is considered impossible to determine positively the nature of the dark condensed material within the Golgi complex. The characteristics of the immature neurosecretory granules and the possibility of releasing neurosecretory products into the cytoplasm already within the perikarya are speculated.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00935990
