Hypophysiotrophic neurons are capable of altering the ratio of co-packaged neurohormones
|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||Adrenalectomy — Animals — Axons/physiology/ultrastructure — Corticotropin-Releasing Hormone/ physiology — Immunohistochemistry — Male — Microscopy, Immunoelectron — Neurons/ physiology — Neurotransmitter Agents/ physiology — Pituitary Gland, Posterior/ cytology/physiology — Rats — Rats, Inbred Strains — Vasopressins/physiology|
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|Research group||Progéniteurs neuronaux|