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Hypophysiotrophic neurons are capable of altering the ratio of co-packaged neurohormones

Bertini, L. T.
Published in Neuroscience. 1991, vol. 42, no. 1, p. 237-244
Abstract Neuronal dense-core vesicles provide a mechanism whereby peptide messengers are secreted in discrete quanta. Here we report on the capacity of rat hypophysiotrophic corticotropin releasing factor-41 neurons to alter the peptide content as well as the size of dense-core vesicles after removal of glucocorticoid negative feedback by adrenalectomy. We demonstrate, using quantitative immunoelectron microscopy, that long-term adrenalectomy induces a progressive increase in the ratio of vasopressin to corticotropin releasing factor-41-immunoreactive sites in the dense-core vesicle compartment. The intravesicular concentration of vasopressin appeared to be the variable parameter while that of the corticotropin releasing factor-41 remained stable at all survival times after adrenalectomy. Moreover, observations for up to 5 weeks indicate that adrenalectomy results in a progressive increase in the mean volume of dense-core vesicles to about three times normal. These results suggest that the quantal size and the composition of dense-core vesicles are subject to long-term modulation. The capacity of corticotropin releasing factor-41 neurons to alter dense-core vesicles could enhance or diminish the efficacy of the hypothalamohypophyseal communication underlying physiological adaptation to stress, as well as pathological changes.
Keywords AdrenalectomyAnimalsAxons/physiology/ultrastructureCorticotropin-Releasing Hormone/ physiologyImmunohistochemistryMaleMicroscopy, ImmunoelectronNeurons/ physiologyNeurotransmitter Agents/ physiologyPituitary Gland, Posterior/ cytology/physiologyRatsRats, Inbred StrainsVasopressins/physiology
Stable URL http://archive-ouverte.unige.ch/unige:10027
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PMID: 1677744
Research group Progéniteurs neuronaux

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Deposited on : 2010-08-06

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