Oxytocin and ADH secretion in relation to electrical activity in antidromically identified supraoptic and paraventricular units
TLDR
Electrical recordings were made from antidromically identified supraoptic and paraventricular units during intracarotid injections of hypertonic and isotonic sodium chloride solutions in rats to study the effects of these injections onopsis and EMT.Abstract:
1. Electrical recordings were made from antidromically identified supraoptic and paraventricular units during intracarotid injections of hypertonic and isotonic sodium chloride solutions in rats.
2. The blood concentrations of vasopressin and oxytocin were estimated by bio-assay before and at different intervals after similar injections.
3. Although a significant change in the action potential activity of the supraoptic nucleus was associated with hormone release, the results were not entirely consistent with a simple relationship between action potential activity and hormone secretion. Firstly, although some units were excited by the stimulus a substantial number were inhibited. Secondly, the blood concentration of the hormones, particularly ADH, remained elevated for longer than might have been expected if additional hormone had ceased to be secreted as soon as firing rates had returned to control values.
4. There were substantial differences between the initial blood concentrations of vasopressin and oxytocin but the firing rates of units in the supraoptic and paraventricular nuclei appeared to be the same.
5. Although significantly less paraventricular than supraoptic units were affected by hypertonic injections the blood concentration of oxytocin was increased by a factor of 8 whereas that of vasopressin was increased by a factor of 2·7.read more
Citations
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Journal ArticleDOI
Electrophysiology of hypothalamic magnocellular neurones secreting oxytocin and vasopressin
TL;DR: The hypothesis that nerve cells are true secreting cells, and act upon one other and upon the cells of other organs by the passage of a chemical substance of the nature of a ferment or proferment from the first cell to the second is formed.
Journal ArticleDOI
Electrophysiological evidence for the activation of supraoptic neurones during the release of oxytocin.
D. W. Lincoln,J. B. Wakerley +1 more
TL;DR: Antidromically identified supraoptic units were recorded in lactating rats anaesthetized with urethane, and their activity was studied during milk ejection evoked by the suckling of the young.
Journal ArticleDOI
Electrophysiological differentiation of oxytocin-and vasopressin-secreting neurones
TL;DR: It is suggested that the rate of vasopressin secretion into the circulation largely depends on the proportion of vasipressin neurones firing phasically, their firing rates within the phases and the duration and degree of synchronization of the phases.
Journal ArticleDOI
Comparison of firing patterns in oxytocin- and vasopressin-releasing neurones during progressive dehydration
TL;DR: Both vasopressin and oxytocin neurones are activated during chronic dehydration, but there is a marked difference in the pattern of their response, which is important in increasing the occurrence of short interspike intervals and thus facilitating hormone release.
Journal ArticleDOI
Morphological and electrophysiological classification of hypothalamic supraoptic neurons
TL;DR: The firing patterns of activated OT and VP neurons often differ, but can transiently appear indistinguishable in vivo and especially in vitro, and classification in vitro without immunochemical labelling may be aided by the presence of phasic bursting and by the differential response of these neurons to certain neurochemicals or to stimulation of certain inputs.
References
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Activity of single neurones in the hypothalamus: effect of osmotic and other stimuli.
B. A. Cross,J. D. Green +1 more
Journal ArticleDOI
Electrical Properties of Hypothalamic Neuroendocrine Cells
TL;DR: This finding suggests that the concept of the neuroendocrine cell as a neuron whose axon forms contacts only on blood vessels and not on other neurons or effector cells is too restrictive.
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Activity of neurones in the paraventricular nucleus of the hypothalamus and its control.
TL;DR: Activity of the paraventricular nucleus neurones was recorded by micro‐electrodes during resting conditions and while various osmotic, chemical, direct and indirect neural stimuli were applied and correlated with evidence of oxytocin release by recording milk ejection responses.
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