Identification of an efferent projection from the paraventricular nucleus of the hypothalamus terminating close to spinally projecting rostral ventrolateral medullary neurons

Pyner, Susan; Coote, John H.

doi:10.1016/s0306-4522(98)00255-3

Cited by 105 publications

(72 citation statements)

References 39 publications

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“…The PVN lies adjacent to the third ventricle in the anterior hypothalamus, and it is composed of magnocellular neurons (MCNs) and parvocellular neurons (PCN). The PCN send projections to autonomic nuclei, such as the rostral ventrolateral medulla (RVLM) and intermediolateral cell column located in the brain stem and spinal cord, respectively (7,24,30). Both of these cardiovascular centers are involved in the control of sympathetic function and the maintenance of arterial BP.…”

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confidence: 99%

Salt-induced sympathoexcitation involves vasopressin V_1a receptor activation in the paraventricular nucleus of the hypothalamus

Ribeiro

Panizza

Santos

et al. 2015

American Journal of Physiology-Regulatory, Integrative and Comp

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-A high-salt diet can lead to hydromineral imbalance and increases in plasma sodium and osmolality. It is recognized as one of the major contributing factors for cardiovascular diseases such as hypertension. The paraventricular nucleus (PVN) plays a pivotal role in osmotically driven sympathoexcitation and high blood pressure, the precise mechanisms of which are not fully understood. Recent evidence indicates that AVP released from magnocellular neurons might be involved in this process. Using a combination of in vivo and in situ studies, we sought to investigate whether AVP, acting on PVN neurons, can change mean arterial pressure (MAP) and sympathetic nerve activity (SNA) in euhydrated male rats. Furthermore, we wanted to determine whether V 1a receptors on PVN neurons would be involved in saltinduced sympathoexcitation and hypertension. In rats, 4 days of salt loading (NaCl 2%) elicited a significant increase in plasma osmolality (39 Ϯ 7 mosmol/kgH 2O), an increase in MAP (26 Ϯ 2 mmHg, P Ͻ 0.001), and sympathoexcitation compared with euhydrated rats. Microinjection of AVP into the PVN of conscious euhydrated animals (100 nl, 3 M) elicited a pressor response (14 Ϯ 2 mmHg) and a significant increase in lumbar SNA (100 nl, 1 mM) (19 Ϯ 5%). Pretreatment with a V 1a receptor antagonist, microinjected bilaterally into the PVN of salt-loaded animals, elicited a decrease in lumbar SNA (Ϫ14 Ϯ 5%) and MAP (Ϫ19 Ϯ 5 mmHg), when compared with the euhydrated group. Our findings show that AVP plays an important role in modulating the salt-induced sympathoexcitation and high blood pressure, via V 1a receptors, within the PVN of male rats. As such, V 1a receptors in the PVN might contribute to neurogenic hypertension in individuals consuming a high-salt diet.vasopressin; paraventricular nucleus of the hypothalamus; salt loading; sympathoexcitation; hypertension A HIGH DIETARY INTAKE OF SALT is one of the major contributing factors to cardiovascular diseases, such as hypertension (11,12,32). High-salt diets can lead to a hydromineral imbalance and increases the plasma sodium concentrations and osmolality. This, in turn, can activate central hypothalamic nuclei that elevate sympathetic outflow and arterial blood pressure (BP), leading to a disorder referred to as salt-sensitive neurogenic hypertension (33).Osmotic perturbations are primarily sensed by osmosensing neurons located in brain regions that lack a blood-brain barrier termed circumventricular organs (CVOs). Under systemic hyperosmotic conditions, the CVOs are activated and send excitatory inputs to the paraventricular nucleus of the hypothalamus (PVN), an important integrative center involved in the autonomic and neuroendocrine functions to maintain body fluids and cardiovascular homeostasis (14,19,28). The PVN lies adjacent to the third ventricle in the anterior hypothalamus, and it is composed of magnocellular neurons (MCNs) and parvocellular neurons (PCN). The PCN send projections to autonomic nuclei, such as the rostral ventrolateral medulla (RVLM) and intermediola...

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Salt-induced sympathoexcitation involves vasopressin V_1a receptor activation in the paraventricular nucleus of the hypothalamus

Ribeiro

Panizza

Santos

et al. 2015

American Journal of Physiology-Regulatory, Integrative and Comp

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“…It is known that PVN has both direct infl uence on sympathetic centres of the spinal cord and indirect one on them via RVLM [13]. Thus, under the infl uence of PVN the adaptive changes of the vasomotor centres run accordingly to changes of the external and internal environment.…”

Section: Discussionmentioning

confidence: 99%

“…nNOS also was found in 6-10 % of neurons with spinal projections [8][9][10] and in 12-25 % neurons with projection into the rostral ventrolateral medulla (RVLM) [11][12][13]. Nevertheless, there is an opinion that the magnocellular neurosecretory neurons are the main source of nitric oxide in PVN [7,14].…”

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confidence: 99%

Features of the inducible nitric oxide synthase expression in paraventricular and supraoptic nuclei of hypothalamus in different models of arterial hypertension

Kolesnyk¹,

Kuzo²,

Hancheva³

et al. 2016

ZMJ

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The regulation of the paraventricular (PVN) and supraoptic (SON) nuclei's activity is carried out with a great amount of different neurotransmitters, in particular, with nitric oxide. In order to get clear understanding of the local NO effects in hypothalamus in normal condition and different models of hypertension it is necessary to study all isoforms of NOS in PVN and SON.Our purpose was to fi nd out the features of the inducible nitric oxide synthase (iNOS) expression in magnocellular SON and PVN in SHR and endocrine-saline model of hypertension in rats.Materials and methods. For all rats the mean blood pressure (mBP) was measured. In Wistar rats mBP was stable during the experiment. In SHR mBP was higher than normal. In animals of the 3 rd group with ESM the fi rst measurement (before the modelling) demonstrated normal rates of mBP. Since the 7 th day of modelling mBP started increase and became steadily increased from the 21 st day. We obtained the frontal slices of hypothalamus and performed the assessment of iNOS expression using immunofl uorescence assay.The results showed the presence of the constitutive expression of iNOS in the magnocellular neurons of hypothalamus in Wistar rats as well as in both groups of experimental hypertension. The level of iNOS expression in magnocellular nuclei was dependent both on type of hypertension and topography of magnocellular neurons in hypothalamus. In SHR there was high expression of iNOS in PVN and low one in SON, whereas in endocrine-saline model there was high expression in SON and there were no substantial changes of the iNOS expression in PVN.Conclusions. We believe the alteration of iNOS expression in magnocellular nuclei of hypothalamus could participate in development and/or adaptation to hypertension. Особливості експресії індуцибельної синтази оксиду азоту в паравентрикулярному та супраоптичному ядрах гіпоталамуса при різних моделях артеріальної гіпертензії Ю. М. Колесник, Н. В. Кузьо, О. В. Ганчева, А. В. АбрамовРегуляція активності супраоптичного (СОЯ) та паравентрикулярного (ПВЯ) ядер здійснюється внаслідок великої кількості ней-ротрансміттерів, зокрема оксиду азоту (NO). Вважаємо, що для отримання чіткого розуміння локальних ефектів NO в гіпоталамусі необхідно дослідити експресію всіх ізоформ синтази оксиду азоту в ПВЯ та СОЯ.Мета роботи -встановлення особливостей експресії індуцибельної синтази оксиду азоту (iNOS) у великоклітинних СОЯ та ПВЯ гіпоталамуса в SHR і за умов ендокринно-сольової моделі (ЕСМ) артеріальної гіпертензії в щурів.Матеріали та методи. Усім щурам виміряли середній артеріальний тиск (сАТ). У щурів лінії Wistar сАТ був стабільним протягом експерименту. У щурів лінії SHR сАТ був стабільно підвищений. У щурів ЕСМ до початку моделювання сАТ був нормальним. З 7 доби моделювання сАТ підвищувався та став стабільно підвищеним, починаючи з 21 доби моделювання. Отримали фронтальні зрізи гіпоталамуса та виконали оцінювання експресії iNOS у них за допомогою імунофлуоресцентного аналізу.Результати. Дослідження показало наявність конституційної...

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“…The responses would therefore depend on location of injectate, spread and intermingling of dendritic fields, which is extensive (Van den Pol, 1982), and destination of axons projecting from neurones in the different areas of PVN. Thus, of the caudally projecting PVN neurones, some project to the parabrachial nucleus (Moga et al 1990), some to the periaqueductal grey (Luiten et al 1985), some to the NTS (Saper et al 1976), some to the rostral ventrolateral medulla (Luiten et al 1985;Pyner & Coote, 1999), and some to the spinal cord (Luiten et al 1985;Swanson, 1987;Strack et al 1989;Hosoya et al 1991;Ranson et al 1997). …”

Section: Discussionmentioning

confidence: 99%

“…Small neurones with dendrites and axons confined to the PVN have been described as making axo-dendritic synapses with parvocellular neurones whose axons pass out of the nucleus ( Van den Pol, 1982). On the other hand, the effects may be due to activating cells comprising mixed pathways from PVN to the rostral ventrolateral medulla (RVLM) andÏor to the spinal cord (Swanson, 1987;Strack et al 1989;Pyner & Coote, 1999). The predominantly inhibitory response of RSNA seen in the present study appears at variance with a study from this laboratory by Malpas & Coote (1994) in which an increase in RSNA accompanied a pressor response on activation of PVN neurones.…”

Section: Discussionmentioning

confidence: 99%

Paraventricular Neurones Elicit a Volume Expansion‐Like Change of Activity in Sympathetic Nerves to the Heart and Kidney in the Rabbit

Deering

Coote

2000

Experimental Physiology

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The role of the paraventricular nucleus (PVN) of the hypothalamus in the cardiovascular response induced by blood volume expansion was examined in anaesthetised rabbits, in which simultaneous recordings were made from a renal sympathetic nerve and one of other sympathetic nerves, the inferior cardiac nerve, a splanchnic nerve and an adrenal nerve. Activation of PVN neurones, by discrete injections (25‐100 nl) of d,l‐homocysteic acid (DLH, 0.2 M) produced one main pattern of sympathetic nerve activity accompanying a pressor response (57‐86% of PVN sites). This was a decrease in renal sympathetic activity (27 +/− 12%) and an increase in splanchnic (60 +/− 12%), adrenal (31 +/− 9%) and cardiac (42 +/− 8%) sympathetic activity. Sites in the PVN from which these combinations of nerve activity were obtained were not confined to a specific subnucleus. An increase in renal sympathetic activity which was reversed to a decrease by reducing the volume of DLH injected was obtained at 10 sites in the PVN. These sites were mainly located in the dorsal parvocellular subnucleus. Varying combinations of sympathetic activation were obtained at a minority of sites. It is concluded that the PVN can evoke a differential pattern of sympathetic discharge which may be functionally significant in the control of blood volume regulation, as it mimics that seen on acute volume expansion.

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Identification of an efferent projection from the paraventricular nucleus of the hypothalamus terminating close to spinally projecting rostral ventrolateral medullary neurons

Cited by 105 publications

References 39 publications

Salt-induced sympathoexcitation involves vasopressin V_1a receptor activation in the paraventricular nucleus of the hypothalamus

Salt-induced sympathoexcitation involves vasopressin V_1a receptor activation in the paraventricular nucleus of the hypothalamus

Features of the inducible nitric oxide synthase expression in paraventricular and supraoptic nuclei of hypothalamus in different models of arterial hypertension

Paraventricular Neurones Elicit a Volume Expansion‐Like Change of Activity in Sympathetic Nerves to the Heart and Kidney in the Rabbit

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Identification of an efferent projection from the paraventricular nucleus of the hypothalamus terminating close to spinally projecting rostral ventrolateral medullary neurons

Cited by 105 publications

References 39 publications

Salt-induced sympathoexcitation involves vasopressin V1a receptor activation in the paraventricular nucleus of the hypothalamus

Salt-induced sympathoexcitation involves vasopressin V1a receptor activation in the paraventricular nucleus of the hypothalamus

Features of the inducible nitric oxide synthase expression in paraventricular and supraoptic nuclei of hypothalamus in different models of arterial hypertension

Paraventricular Neurones Elicit a Volume Expansion‐Like Change of Activity in Sympathetic Nerves to the Heart and Kidney in the Rabbit

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Salt-induced sympathoexcitation involves vasopressin V_1a receptor activation in the paraventricular nucleus of the hypothalamus

Salt-induced sympathoexcitation involves vasopressin V_1a receptor activation in the paraventricular nucleus of the hypothalamus