ISSN:
1432-0878
Keywords:
Supraoptic nucleus
;
Neurohypophysis
;
Neurosecretion
;
Axonal transport
;
Colchicine
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary The effect of colchicine on the transport of proteins in the hypothalamo-neurohypophyseal tract of the rat was studied after injection of (35S) cysteine into the supraoptic nucleus (SON) region. Colchicine, dissolved in distilled water and administered subarachnoidally, inhibited the axonal transport of labelled proteins into the neurohypophysis: the radioactivity that was recovered in neurohypophyseal TCA precipitable material was markedly decreased and hardly any radioactivity was found in the neurohypophyseal proteins which were separated by polyacrylamide gel disc electrophoresis. As revealed by electron microscopy the SON cell bodies showed marked changes after treatment with colchicine: a deeply folded nucleolemma; a pronounced, granular nucleolus; a dispersed chromatin; a zonal distribution of cell organelles with mitochondria and lysosomes accumulated at the periphery, crowded ribosomes, often arranged as polyribosomes and richly branching short profiles of endoplasmic reticulum filled with filamentous material forming an inner perinuclear zone separated by enlarged Golgi complexes. The profiles of elongated Herring bodies in the infundibulum were increased. The axon terminals were filled with heavily osmiophilic neurosecretory granules. The neurofilaments were slightly or moderately increased in number. No apparent changes were observed with regard to the neurotubuli in the SON neurons. The glial cells of the supraopticoneurohypophyseal tract showed reactive changes with a proliferation of filamentous elements. The biochemical and ultrastructural findings are discussed especially with respect to the mechanisms of transport and release of neurosecretory granules.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00339421
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