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Biomedical subjects

L B Geffen

Publications and source records attributed to L B Geffen.

At least 73 records · Page 4Linked to original sources
PubMed1971

Action of 6-hydroxydopamine on lamb sympathetic ganglia, vas deferens and adrenal medulla: a combined histochemical, ultrastructural and biochemical comparison with the effects of reserpine.

1. The effects of a single dose of 6-hydroxydopamine (6-OHDA) compared with those of chronic reserpine treatment were studied in lamb sympathetic neurones and adrenal medulla by a combination of fluorescence histochemistry, electron microscopy and radiochemical assay.2. In sympathetic ganglia, 6-OHDA produced a rise in noradrenaline concentration within 24 h, and falls in tyrosine hydroxylase and monoamine oxidase activities, whereas reserpine caused a fall in noradrenaline, a rise in tyrosine hydroxylase activity and no change in monoamine oxidase activity. The fluorescence of intra- and postganglionic axons increased greatly within 24 h of 6-OHDA, and there was a corresponding accumulation of large dense-core vesicles within many axons whose neurotubules were disrupted. The changes were almost reversed after 3 weeks.3. In the vas deferens, the concentration of noradrenaline and tyrosine hydroxylase and monoamine oxidase activities had all fallen 24 h after 6-OHDA treatment and had started to recover 3 weeks later. In the adrenal medulla, 6-OHDA did not alter NA concentrations but increased tyrosine hydroxylase activity whereas reserpine depleted noradrenaline and increased tyrosine hydroxylase activity.4. The changes produced in sympathetic ganglia by 6-OHDA may be due both to a direct action on the axoplasmic transport of noradrenaline containing vesicles and indirectly to the reaction of the neurones to loss of the integrity of their axons.

Adrenal Medulla↗
PubMed1969

Distribution of granular vesicles in normal and constricted sympathetic neurones.

1. A quantitative analysis has been made of the characteristics of granular vesicles in different parts of normal and ligated post-ganglionic sympathetic neurones supplying the cat spleen. The least diameter of the vesicle membrane and its electron-dense core was measured from electron micrographs with an automated particle size analyser.2. Vesicles of average diameter 443 A, with and without electron-dense cores (192 A), were concentrated in the axon terminals of the spleen, whereas in the cell bodies in the coeliac ganglion and their axons there were only a few large vesicles (787 A) with large granules (562 A).3. Ligation of the splenic nerves for 24 hr resulted in an accumulation proximal to the constriction of granular vesicles significantly larger (688 A) and more completely granulated (478 A) than those in the terminals.4. Reserpine reduced the number of vesicles with granular cores without discrimination between the two populations.5. Since the distribution of noradrenaline in sympathetic neurones can be correlated with the presence of large as well as small granular vesicles, it is suggested that the larger, more granular type found mainly proximally in the neurone is in transit from its perikaryal site of synthesis to the axon terminals, where it is transformed into the smaller synaptic vesicles.

Animals↗
PubMed1969

Immunohistochemical localizatio of protein components of catecholamine storage vesicles.

1. The distribution of specific proteins in sympathetic neurones has been examined by immunofluorescent histology using antibodies prepared against soluble protein components of the catecholamine storage vesicles of the adrenal medulla.2. Two antigen preparations were separated by ion exchange chromatography of the soluble proteins released on osmotic lysis of catecholamine storage vesicles which had been isolated by centrifugation from homogenates of sheep adrenal medulla. One fraction (AgDH) had high dopamine-beta-hydroxylase activity, while another (AgCB), consisting of the bulk of the protein, had some capacity to bind catecholamines. On disk gel electrophoresis the antigens ran as single bands with very different mobilities.3. Antisera (AsDH) and (AsCB) produced in rabbits to the two antigens were shown to react specifically with their antigens by immunodiffusion and electrophoresis in agarose.4. Indirect immunofluorescent staining of tissue sections was achieved by layering first the rabbit anti-sera, followed by goat anti-rabbit globulin serum which had been conjugated with fluorescein isothiocyanate.5. The adrenal medulla and the cell bodies of sympathetic ganglia showed the most intense green fluorescence with the immune rabbit sera, and hardly stained when pre-immune serum from the same animal was used. The reactivity of the antisera could be abolished by incubation with the corresponding antigen.6. The preterminal and terminal axons of sympathetic nerves also stained specifically but less intensely with both antisera. When the nerves were ligated for up to 24 hr, the portion immediately proximal to the constriction showed an enhanced reaction to the antisera.7. The results provide evidence that sympathetic neurones contain proteins immunologically identical to those involved in the synthesis and storage of noradrenaline in the adrenal medulla, and support the concept that granular vesicles are synthesized in the perikaryon of the neurone and are transported somatofugally in the axon.

Adrenal Medulla↗