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Sean D Stocker - One of the best experts on this subject based on the ideXlab platform.
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integration of hypernatremia and angiotensin ii by the Organum vasculosum of the lamina terminalis regulates thirst
The Journal of Neuroscience, 2020Co-Authors: Brian J Kinsman, Kirsteen N Browning, Megan M Wenner, William B Farquhar, Sarah S Simmonds, Sean D StockerAbstract:The Organum vasculosum of the lamina terminalis (OVLT) contains NaCl-sensitive neurons to regulate thirst, neuroendocrine function, and autonomic outflow. The OVLT also expresses the angiotensin II (AngII) type1 receptor, and AngII increases Fos expression in OVLT neurons. The present study tested whether individual OVLT neurons sensed both NaCl and AngII to regulate thirst and body fluid homeostasis. A multifaceted approach, including in vitro whole-cell patch recordings, in vivo single-unit recordings, and optogenetic manipulation of OVLT neurons, was used in adult, male Sprague Dawley rats. First, acute intravenous infusion of hypertonic NaCl or AngII produced anatomically distinct patterns of Fos-positive nuclei in the OVLT largely restricted to the dorsal cap versus vascular core, respectively. However, in vitro patch-clamp recordings indicate 66% (23 of 35) of OVLT neurons were excited by bath application of both hypertonic NaCl and AngII. Similarly, in vivo single-unit recordings revealed that 52% (23 of 44) of OVLT neurons displayed an increased discharge to intracarotid injection of both hypertonic NaCl and AngII. In marked contrast to Fos immunoreactivity, neuroanatomical mapping of Neurobiotin-filled cells from both in vitro and in vivo recordings revealed that NaCl- and AngII-responsive neurons were distributed throughout the OVLT. Next, optogenetic excitation of OVLT neurons stimulated thirst but not salt appetite. Conversely, optogenetic inhibition of OVLT neurons attenuated thirst stimulated by hypernatremia or elevated AngII but not hypovolemia. Collectively, these findings provide the first identification of individual OVLT neurons that respond to both elevated NaCl and AngII concentrations to regulate thirst and body fluid homeostasis. SIGNIFICANCE STATEMENT Body fluid homeostasis requires the integration of neurohumoral signals to coordinate behavior, neuroendocrine function, and autonomic function. Extracellular NaCl concentrations and the peptide hormone angiotensin II (AngII) are two major neurohumoral signals that regulate body fluid homeostasis. Herein, we present the first compelling evidence that individual neurons located in the Organum vasculosum of the lamina terminalis detect both NaCl and AngII. Furthermore, optogenetic interrogations demonstrate that these neurons play a pivotal role in the regulation of thirst stimulated by NaCl and AngII. These novel observations lay the foundation for future investigations for how such inputs as well as others converge onto unique Organum vasculosum of the lamina terminalis neurons to coordinate body fluid homeostasis and contribute to disorders of fluid balance.
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abstract 107 neurons in the Organum vasculosum of the lamina terminalis sense nacl and angiotensin ii to regulate sympathetic nerve activity and arterial blood pressure
Hypertension, 2018Co-Authors: Sean D Stocker, Brian J Kinsman, Kirsteen N Browning, Megan M Wenner, William B FarquharAbstract:The Organum vasculosum of the lamina terminalis (OVLT) contains specialized neurons that sense changes in extracellular NaCl concentrations to regulate sympathetic nerve activity (SNA) and arterial...
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Organum vasculosum laminae terminalis contributes to increased sympathetic nerve activity induced by central hyperosmolality
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2007Co-Authors: Sean D Stocker, Glenn M ToneyAbstract:The contribution of the Organum vasculosum laminae terminalis (OVLT) in mediating central hyperosmolality-induced increases of sympathetic nerve activity (SNA) and arterial blood pressure (ABP) was...
Charles W Bourque - One of the best experts on this subject based on the ideXlab platform.
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anatomical organization of the rat Organum vasculosum laminae terminalis
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2015Co-Authors: Masha Pragerkhoutorsky, Charles W BourqueAbstract:The Organum vasculosum of the laminae terminalis (OVLT) is a circumventricular organ located along the ventral part of the anterior wall of the third ventricle. Because it lacks a complete blood-br...
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Circumventricular Organs: Gateways to the Brain Axonal Projections From The Organum Vasculosum Lamina Terminalis To The Supraoptic Nucleus: Functional Analysis And Presynaptic Modulation
Clinical and Experimental Pharmacology and Physiology, 2001Co-Authors: Charles W Bourque, Dominique RichardAbstract:SUMMARY 1. The rat Organum vasculosum lamina terminalis (OVLT) contains GABA- and glutamate-releasing neurons that project directly to magnocellular neurosecretory cells (MNC) in the supraoptic nucleus. 2. Changes in osmolality over the OVLT in hypothalamic explants cause proportional changes in firing in MNC through corresponding changes in the frequency of spontaneous glutamatergic excitatory post-synaptic potentials without affecting GABAergic inhibitory post-synaptic potentials. 3. Exogenously applied atrial natriuretic peptide inhibits the osmotic control of MNC by causing a decrease in the amount of glutamate released provoked by action potentials originating from OVLT neurons.
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Osmoregulation of vasopressin neurons: a synergy of intrinsic and synaptic processes.
Progress in Brain Research, 1998Co-Authors: Charles W BourqueAbstract:Abstract The release of vasopressin into the general circulation varies as a function of plasma osmolality and therefore plays a major role in systemic osmoregulation. In vivo, the secretion of this hormone in the neurohypophysis is primarily determined by the rate of action potential discharge of the magnocellular neurosecretory cells (MNCs) in the hypothalamus. Experiments done over the past 20 years have clarified much of the neurophysio-logical basis underlying this important osmoregulatory reflex. As discussed here, recent findings indicate that the regulation of the firing rate of MNCs during changes in systemic osmolality involves the concerted modulation of mechanosensitive ion channels in MNCs, as well as excitatory glutamatergic inputs derived from forebrain regions such as the Organum vasculosum of the lamina terminalis.
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membrane properties of Organum vasculosum lamina terminalis neurons recorded in vitro
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 1993Co-Authors: R Nissen, Charles W Bourque, Leo P RenaudAbstract:Intracellular recordings of Organum vasculosum lamina terminalis (OVLT) neurons were obtained from superfused explants of rat hypothalamus. Most (32 of 34) OVLT neurons displayed a low threshold spike response during depolarizing pulses applied from holding membrane potentials negative to -70 mV. In 17 of 34 cells, electrical stimulation of the supraoptic nucleus area evoked antidromic responses. In 20 of the 34 cells, 8 of which were antidromically driven, identical stimuli also revealed either excitatory (n = 12) or inhibitory (n = 5) or mixed (n = 3) postsynaptic potentials. Axonal projections to the ipsilateral supraoptic nucleus were confirmed afterwards using reconstruction of Lucifer yellow-filled cells. A 10-40 mosmol/kgH2O increase in the osmolality of the superfusion media by addition of NaCl or mannitol prompted a membrane depolarization of 2-10 mV in each of nine OVLT neurons tested. These results indicate that OVLT neurons project to the supraoptic nucleus and possess intrinsic properties capable of influencing their excitability. Because neurons in OVLT depolarize consequent to elevations in media osmolality, the OVLT may provide a means by which hyperosmotic stimuli influence neuroendocrine function.
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synaptic activation of rat supraoptic neurons by osmotic stimulation of the Organum vasculosum lamina terminalis
Neuroendocrinology, 1992Co-Authors: Dominique Richard, Charles W BourqueAbstract:Intracellular recordings were obtained from neurons of the supraoptic nucleus in superfused explants of rat hypothalamus in vitro. Transient hyperosmotic stimulation of the Organum vasculosum lamina terminalis (OVLT) area caused long-lasting increases in the frequency of excitatory post-synaptic potentials and an associated rise in the rate of action potential discharge. Such responses could be evoked by small (
William B Farquhar - One of the best experts on this subject based on the ideXlab platform.
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integration of hypernatremia and angiotensin ii by the Organum vasculosum of the lamina terminalis regulates thirst
The Journal of Neuroscience, 2020Co-Authors: Brian J Kinsman, Kirsteen N Browning, Megan M Wenner, William B Farquhar, Sarah S Simmonds, Sean D StockerAbstract:The Organum vasculosum of the lamina terminalis (OVLT) contains NaCl-sensitive neurons to regulate thirst, neuroendocrine function, and autonomic outflow. The OVLT also expresses the angiotensin II (AngII) type1 receptor, and AngII increases Fos expression in OVLT neurons. The present study tested whether individual OVLT neurons sensed both NaCl and AngII to regulate thirst and body fluid homeostasis. A multifaceted approach, including in vitro whole-cell patch recordings, in vivo single-unit recordings, and optogenetic manipulation of OVLT neurons, was used in adult, male Sprague Dawley rats. First, acute intravenous infusion of hypertonic NaCl or AngII produced anatomically distinct patterns of Fos-positive nuclei in the OVLT largely restricted to the dorsal cap versus vascular core, respectively. However, in vitro patch-clamp recordings indicate 66% (23 of 35) of OVLT neurons were excited by bath application of both hypertonic NaCl and AngII. Similarly, in vivo single-unit recordings revealed that 52% (23 of 44) of OVLT neurons displayed an increased discharge to intracarotid injection of both hypertonic NaCl and AngII. In marked contrast to Fos immunoreactivity, neuroanatomical mapping of Neurobiotin-filled cells from both in vitro and in vivo recordings revealed that NaCl- and AngII-responsive neurons were distributed throughout the OVLT. Next, optogenetic excitation of OVLT neurons stimulated thirst but not salt appetite. Conversely, optogenetic inhibition of OVLT neurons attenuated thirst stimulated by hypernatremia or elevated AngII but not hypovolemia. Collectively, these findings provide the first identification of individual OVLT neurons that respond to both elevated NaCl and AngII concentrations to regulate thirst and body fluid homeostasis. SIGNIFICANCE STATEMENT Body fluid homeostasis requires the integration of neurohumoral signals to coordinate behavior, neuroendocrine function, and autonomic function. Extracellular NaCl concentrations and the peptide hormone angiotensin II (AngII) are two major neurohumoral signals that regulate body fluid homeostasis. Herein, we present the first compelling evidence that individual neurons located in the Organum vasculosum of the lamina terminalis detect both NaCl and AngII. Furthermore, optogenetic interrogations demonstrate that these neurons play a pivotal role in the regulation of thirst stimulated by NaCl and AngII. These novel observations lay the foundation for future investigations for how such inputs as well as others converge onto unique Organum vasculosum of the lamina terminalis neurons to coordinate body fluid homeostasis and contribute to disorders of fluid balance.
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abstract 107 neurons in the Organum vasculosum of the lamina terminalis sense nacl and angiotensin ii to regulate sympathetic nerve activity and arterial blood pressure
Hypertension, 2018Co-Authors: Sean D Stocker, Brian J Kinsman, Kirsteen N Browning, Megan M Wenner, William B FarquharAbstract:The Organum vasculosum of the lamina terminalis (OVLT) contains specialized neurons that sense changes in extracellular NaCl concentrations to regulate sympathetic nerve activity (SNA) and arterial...
Brian J Kinsman - One of the best experts on this subject based on the ideXlab platform.
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integration of hypernatremia and angiotensin ii by the Organum vasculosum of the lamina terminalis regulates thirst
The Journal of Neuroscience, 2020Co-Authors: Brian J Kinsman, Kirsteen N Browning, Megan M Wenner, William B Farquhar, Sarah S Simmonds, Sean D StockerAbstract:The Organum vasculosum of the lamina terminalis (OVLT) contains NaCl-sensitive neurons to regulate thirst, neuroendocrine function, and autonomic outflow. The OVLT also expresses the angiotensin II (AngII) type1 receptor, and AngII increases Fos expression in OVLT neurons. The present study tested whether individual OVLT neurons sensed both NaCl and AngII to regulate thirst and body fluid homeostasis. A multifaceted approach, including in vitro whole-cell patch recordings, in vivo single-unit recordings, and optogenetic manipulation of OVLT neurons, was used in adult, male Sprague Dawley rats. First, acute intravenous infusion of hypertonic NaCl or AngII produced anatomically distinct patterns of Fos-positive nuclei in the OVLT largely restricted to the dorsal cap versus vascular core, respectively. However, in vitro patch-clamp recordings indicate 66% (23 of 35) of OVLT neurons were excited by bath application of both hypertonic NaCl and AngII. Similarly, in vivo single-unit recordings revealed that 52% (23 of 44) of OVLT neurons displayed an increased discharge to intracarotid injection of both hypertonic NaCl and AngII. In marked contrast to Fos immunoreactivity, neuroanatomical mapping of Neurobiotin-filled cells from both in vitro and in vivo recordings revealed that NaCl- and AngII-responsive neurons were distributed throughout the OVLT. Next, optogenetic excitation of OVLT neurons stimulated thirst but not salt appetite. Conversely, optogenetic inhibition of OVLT neurons attenuated thirst stimulated by hypernatremia or elevated AngII but not hypovolemia. Collectively, these findings provide the first identification of individual OVLT neurons that respond to both elevated NaCl and AngII concentrations to regulate thirst and body fluid homeostasis. SIGNIFICANCE STATEMENT Body fluid homeostasis requires the integration of neurohumoral signals to coordinate behavior, neuroendocrine function, and autonomic function. Extracellular NaCl concentrations and the peptide hormone angiotensin II (AngII) are two major neurohumoral signals that regulate body fluid homeostasis. Herein, we present the first compelling evidence that individual neurons located in the Organum vasculosum of the lamina terminalis detect both NaCl and AngII. Furthermore, optogenetic interrogations demonstrate that these neurons play a pivotal role in the regulation of thirst stimulated by NaCl and AngII. These novel observations lay the foundation for future investigations for how such inputs as well as others converge onto unique Organum vasculosum of the lamina terminalis neurons to coordinate body fluid homeostasis and contribute to disorders of fluid balance.
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abstract 107 neurons in the Organum vasculosum of the lamina terminalis sense nacl and angiotensin ii to regulate sympathetic nerve activity and arterial blood pressure
Hypertension, 2018Co-Authors: Sean D Stocker, Brian J Kinsman, Kirsteen N Browning, Megan M Wenner, William B FarquharAbstract:The Organum vasculosum of the lamina terminalis (OVLT) contains specialized neurons that sense changes in extracellular NaCl concentrations to regulate sympathetic nerve activity (SNA) and arterial...
N Murakami - One of the best experts on this subject based on the ideXlab platform.
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Organum vasculosum laminae terminalis ovlt is a brain site to produce interleukin 1β during fever
Brain Research, 1993Co-Authors: T Nakamori, Akio Morimoto, Kazuhito Yamaguchi, T Watanabe, Nancy C Long, N MurakamiAbstract:Abstract The present study was carried out to determine whether interleukin-1 (IL-1) production occurs in the rabbit Organum vasculosum laminae terminalis (OVLT) during fever induced by endotoxin. The intravenous (i.v.) injection of endotoxin (4 μg/kg) caused significant fever in rabbits. Through the use of in situ hybridization and immunohistochemical techniques, the synthesis of IL-1 was observed in the OVLT during the fever. The present results support the hypothesis that IL-1 is produced in the brain during fever.
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Organum vasculosum laminae terminalis ovlt in rabbit and rat topographic studies
The Journal of Comparative Neurology, 1993Co-Authors: Kazuhito Yamaguchi, Akio Morimoto, N MurakamiAbstract:The microcirculation and fine structure of the rabbit and rat Organum vasculosum laminae terminalis (OVLT) were examined by light microscopy and scanning and transmission electron microscopy. In both animals, the microcirculation is composed of a superficial and a deep vascular bed but the system is more complex and extensive in the rabbit. This was particularly true of the deep vascular bed. In the rabbit, the deep bed is composed of fenestrated capillaries, which are arranged in glomerular tufts surrounded by very wide perivascular spaces (PVS). In contrast, the deep vascular bed of the rat OVLT usually consists of only one or two small vessels. These are either fenestrated and surrounded by a PVS or lined by continuous endothelium with only a few fenestrae and without a dilated PVS. A corresponding difference was seen in the contours of the ventricular surface. It is much more irregular in the rabbit than in the rat and numerous bulges reflect the underlying vascular tufts and pockets of PVS in the rabbit. Supraependymal cells are present in both species and two sizes of them occur in the rabbit. The results demonstrate that the microcirculation of the OVLT is more elaborate and more highly developed in the rabbit than in the rat. We suggest that this might result in a different neurohemal microenvironment and, ultimately, in functional differences.