Excitation of phasically firing supraoptic neurones during vasopressin release

Harris, Mary; Dreifuss, Jean-Jacques; Jj, Legros

doi:10.1038/258080b0

Cited by 66 publications

(46 citation statements)

References 11 publications

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“…Phasic firing is plainly a much more characteristic feature of vasopressin cells than of oxytocin cells, a suggestion that has been made as a result of earlier studies (Dreifuss, Harris & Tribollet, 1976;Harris, Dreifuss & Legros, 1975;Wakerley et al 1975;Poulain et al 1977). Furthermore, it is clear that cells which fire phasically represent one aspect of the activity of cells which may at other times fire continuously or in a less structured pattern.…”

Section: Firing Charracteritstic Of Supraoptic Neuronesmentioning

confidence: 56%

Characterization of the responses of oxytocin‐ and vasopressin‐secreting neurones in the supraoptic nucleus to osmotic stimulation

Brimble¹,

Dyball²

1977

The Journal of Physiology

272

188

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Section: Firing Charracteritstic Of Supraoptic Neuronesmentioning

confidence: 56%

Characterization of the responses of oxytocin‐ and vasopressin‐secreting neurones in the supraoptic nucleus to osmotic stimulation

Brimble¹,

Dyball²

1977

The Journal of Physiology

272

188

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“…There is clear anatomical evidence for connexions between the n.t.s., where the primary baroreceptor and chemoreceptor afferents synapse (Lipski et al 1975;Lipski, McAllen & Trzebski, 1976), and the ventral surface of the medulla (Errington & Dashwood, 1979) and perhaps also Al (Sawchenko & Swanson, 1982). Earlier, Clark & Rocha e Silva (1967) 394 LOCUS COERULEUS AND SUPRAOPTIC NUCLEUS had shown that in the cat bilateral carotid occlusion releases vasopressin only, and Dreifuss et al (1976) found in rats that the same stimulus activated only the phasic neurones of the supraoptic nucleus, and that this also released vasopressin without oxytocin (Harris, Dreifuss & Legros, 1975). Harris (1979) then reported that specific chemoreceptor stimulation also only activates phasic supraoptic neurones in rats.…”

Section: Discussionmentioning

confidence: 99%

Lesions of the locus coeruleus abolish baroreceptor‐induced depression of supraoptic neurones in the rat.

Banks¹,

Harris²

1984

The Journal of Physiology

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SUMMARY1. Urethane-anaesthetized rats were used to investigate the influence of lesions within the locus coeruleus on the inhibition of phasically discharging supraoptic neurones that normally follows the activation of arterial baroreceptors.2. Carotid sinus baroreceptors were stimulated by the inflation of a blind sac of the carotid bifurcation. A general activation of arterial baroreceptors was evoked by increasing arterial blood pressure following the intravenous injection of the pure oc-adrenoreceptor agonist phenylephrine.3. The locus coeruleus of one side only was destroyed either by thermal (radiofrequency) lesions, or by the injection of 6-hydroxydopamine (1 PI, 05 mg/ml). The extent ofeach lesion was assessed histologically in stained tissue and with fluorescence histochemistry. 4. Lesions in locus coeruleus abolished all baroreceptor input to supraoptic neurones on the side ipsilateral to the lesion. The lesions had no effect on the cardiovascular responses to the stimulus, and did not abolish the excitation of supraoptic neurones after ipsilateral carotid body chemoreceptor activation.5. 6-Hydroxydopamine lesions (1 ,u, 2 mg/ml) in the rostral part of the ventrolateral Al catecholamine neurones were less consistent in their abolition of baroreceptor input to the supraoptic nucleus. When the input from ipsilateral carotid sinus baroreceptors was abolished, there was an equivalent effect on the influence of the carotid body chemoreceptors. Input from other arterial baroreceptors, activated by phenylephrine injection, was not affected.6. From these results, it is proposed that the baroreceptor-induced depression of phasically discharging supraoptic neurones is mediated via a direct noradrenergic input from the locus coeruleus.

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“…During the release of VP in response to hypovolemia (29), hypotension (34), and hyperosmolality (8), VP neurons increase their firing rate and adapt a phasic firing pattern comprising alternating periods of activity (7-15 Hz) and silence, each lasting tens of seconds. Plasma OT also increases in response to hypernatremia (32), and OT neurons respond to hyperosmolarity with increases in firing rate (52,67).…”

Section: Discussionmentioning

confidence: 99%

Epithelial Na⁺ sodium channels in magnocellular cells of the rat supraoptic and paraventricular nuclei

Teruyama

Sakuraba

Wilson

et al. 2012

American Journal of Physiology-Endocrinology and Metabolism

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Teruyama R, Sakuraba M, Wilson LL, Wandrey NE, Armstrong WE. Epithelial Na ϩ sodium channels in magnocellular cells of the rat supraoptic and paraventricular nuclei. Am J Physiol Endocrinol Metab 302: E273-E285, 2012. First published November 1, 2011; doi:10.1152/ajpendo.00407.2011.-The epithelial Na ϩ channels (ENaCs) are present in kidney and contribute to Na ϩ and water homeostasis. All three ENaC subunits (␣, ␤, and ␥) were demonstrated in the cardiovascular regulatory centers of the rat brain, including the magnocellular neurons (MNCs) in the supraoptic nucleus (SON) and the paraventricular nucleus (PVN). However, the functional significance of ENaCs in vasopressin (VP) and oxytocin (OT) synthesizing MNCs is completely unknown. In this study, we show with immunocytochemical double-labeling that the ␣-ENaC is colocalized with either VP or OT in MNCs in the SON and PVN. In addition, parvocellular neurons in the dorsal, ventrolateral, and posterior subregions of the PVN (not immunoreactive to VP or OT) are also immunoreactive for ␣-ENaC. In contrast, immunoreactivity to ␤-and ␥-ENaC is colocalized with VP alone within the MNCs. Furthermore, immunoreactivity for a known target for ENaC expression, the mineralcorticoid receptor (MR), is colocalized with both VP and OT in MNCs. Using single-cell RT-PCR, we detected mRNA for all three ENaC subunits and MR in cDNA libraries derived from single MNCs. In whole cell voltage clamp recordings, application of the ENaC blocker benzamil reversibly reduced a steady-state inward current and decreased cell membrane conductance approximately twofold. Finally, benzamil caused membrane hyperpolarization in a majority of VP and about one-half of OT neurons in both spontaneously firing and quiet cells. These results strongly suggest the presence of functional ENaCs that may affect the firing patterns of MNCs, which ultimately control the secretion of VP and OT. aldodsterone; vasopressin; oxytocin THE NEUROHYPOPHYSIAL HORMONES vasopressin (VP) and oxytocin (OT) are synthesized in the magnocellular neurons (MNCs) located within the paraventricular nucleus (PVN) and the supraoptic nucleus (SON) of the hypothalamus and released from the neurohypophysis into the general circulation in response to physiological demands. The secretion of VP increases in response to hyperosmolality, hypovolemia, and hypotension and produces antidiuretic and pressor effects (59). In addition to the well-known effects of OT during parturition and lactation, plasma OT also increases with hyperosmolality and hypernatremia (32) and induces natriuresis (13, 31).The non-voltage-dependent, amiloride-sensitive epithelial Na ϩ channels (ENaCs) are present in the apical membrane of epithelial cells in a variety of tissues, such as urinary bladder, renal collecting duct, distal colon, sweat and salivary glands, lung, and taste buds, and are known to mediate the transport of Na ϩ across epithelia (7, 21). Thus, together with the Na ϩ /K ϩ -ATPase present in the basal membrane of epithelial cells, ENaCs regulate transe...

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Excitation of phasically firing supraoptic neurones during vasopressin release

Cited by 66 publications

References 11 publications

Characterization of the responses of oxytocin‐ and vasopressin‐secreting neurones in the supraoptic nucleus to osmotic stimulation

Characterization of the responses of oxytocin‐ and vasopressin‐secreting neurones in the supraoptic nucleus to osmotic stimulation

Lesions of the locus coeruleus abolish baroreceptor‐induced depression of supraoptic neurones in the rat.

Epithelial Na⁺ sodium channels in magnocellular cells of the rat supraoptic and paraventricular nuclei

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Excitation of phasically firing supraoptic neurones during vasopressin release

Cited by 66 publications

References 11 publications

Characterization of the responses of oxytocin‐ and vasopressin‐secreting neurones in the supraoptic nucleus to osmotic stimulation

Characterization of the responses of oxytocin‐ and vasopressin‐secreting neurones in the supraoptic nucleus to osmotic stimulation

Lesions of the locus coeruleus abolish baroreceptor‐induced depression of supraoptic neurones in the rat.

Epithelial Na+ sodium channels in magnocellular cells of the rat supraoptic and paraventricular nuclei

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Epithelial Na⁺ sodium channels in magnocellular cells of the rat supraoptic and paraventricular nuclei