The dense core of vertebrate central nervous system synapses revealed by potassium permanganate fixation as formed by small membrane-bounded vesicles.
Large dense core vesicles occur in small number in the company of clear synaptic vesicles in various parts of the central nervous system following osmium or aldehydes fixation. When fixed by potassium permanganate large vesicles occur that contain one or more membrane-bounded small spherical vesicles, as is demonstrated in the habenular nuclei of the frog Rana esculenta. On a morphological basis we suppose that the population of this kind of synapse consists of the same type of vesicles, the majority being free while some are enclosed within a larger vesicle. An hypothesis on the meaning of these composite vesicles is presented.
Kemali
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Laboratorio di Cibernetica del C.N.R., 80072 Arco Felice and Stazione Zoologica, Naples, Italy.