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Hypophysiotrophic function of vasopressin and oxytocin
F A Antoni1, K J Kovács, J Dohanits
1Department of Human Anatomy, University of Oxford, England.
Brain Research Bulletin
|June 1, 1988
Summary
Hypothalamic paraventricular nucleus (PVN) lesions alter vasopressin (VP) and oxytocin (OT) release at the median eminence. Oxytocin (OT) shows significant plasticity, increasing after PVN lesioning, suggesting a role in stress response.
Area of Science:
- Neuroendocrinology
- Neurobiology
Background:
- The hypothalamic paraventricular nucleus (PVN) is crucial for regulating neurohormone secretion.
- Vasopressin (VP) and oxytocin (OT) are key neurohormones involved in stress response.
Purpose of the Study:
- To investigate the impact of PVN lesioning on VP and OT secretion at the median eminence.
- To examine the functional and structural plasticity of VP and OT neuronal systems.
Main Methods:
- In vitro incubation of the median eminence to measure neurohormone secretion.
- KCl stimulation to induce neurohormone release.
- Immunohistochemical staining to visualize VP and OT distribution.
Main Results:
- PVN lesioning abolished KCl-induced VP release at 1 week, with partial recovery at 6 weeks.
- OT secretion decreased by 50% at 1 week and increased to 400% of control at 6 weeks post-lesion.
- Increased OT immunoreactive varicosities were observed around portal capillaries 6 weeks after PVN lesioning.
Conclusions:
- VP and OT neuronal systems projecting to the median eminence exhibit significant functional and structural plasticity after PVN lesioning.
- Oxytocin (OT) plays a critical role in regulating pituitary-adrenocortical function in long-term PVN-lesioned rats.