Studies on the dense-core vesicles in the ontogenesis of locus coeruleus. I. Localization, type and density of the dense-core vesicles in locus coeruleus during rat ontogenesis.

In an attempt to clarify the function of dense-core vesicles quantitative estimation is made of their density and localization in the perikarya, axonal boutons and neuropil of rat locus coeruleus during different ontogenetic stages. The results obtained, compared with the fluorescence- and electronmicroscopic data, suggest participation of the dense-core vesicles in the neuronal development and differentiation: presence in the earliest embryonal periods, statistically significant increase in the density in the period of most intensified growth and maturing of the neuropil and axonal boutons, and change in the density of the perikarya in connection with intensified axonal transport. Quantitative data are also presented about the participation of the dense-core vesicles in synaptic transmission.