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Wang J, Lv F, Yin W, Gao Z, Liu H, Wang Z, Sun J. The organum vasculosum of the lamina terminalis and subfornical organ: regulation of thirst. Front Neurosci 2023; 17:1223836. [PMID: 37732311 PMCID: PMC10507174 DOI: 10.3389/fnins.2023.1223836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 08/22/2023] [Indexed: 09/22/2023] Open
Abstract
Thirst and water intake are regulated by the organum vasculosum of the lamina terminalis (OVLT) and subfornical organ (SFO), located around the anteroventral third ventricle, which plays a critical role in sensing dynamic changes in sodium and water balance in body fluids. Meanwhile, neural circuits involved in thirst regulation and intracellular mechanisms underlying the osmosensitive function of OVLT and SFO are reviewed. Having specific Nax channels in the glial cells and other channels (such as TRPV1 and TRPV4), the OVLT and SFO detect the increased Na+ concentration or hyperosmolality to orchestrate osmotic stimuli to the insular and cingulate cortex to evoke thirst. Meanwhile, the osmotic stimuli are relayed to the supraoptic nucleus (SON) and paraventricular nucleus of the hypothalamus (PVN) via direct neural projections or the median preoptic nucleus (MnPO) to promote the secretion of vasopressin which plays a vital role in the regulation of body fluid homeostasis. Importantly, the vital role of OVLT in sleep-arousal regulation is discussed, where vasopressin is proposed as the mediator in the regulation when OVLT senses osmotic stimuli.
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Affiliation(s)
- Jiaxu Wang
- Department of Anatomy and Neurobiology, School of Medicine, Shandong University, Jinan, Shandong, China
| | - Fenglin Lv
- Department of Anatomy and Neurobiology, School of Medicine, Shandong University, Jinan, Shandong, China
| | - Wei Yin
- Department of Anatomy and Neurobiology, School of Medicine, Shandong University, Jinan, Shandong, China
| | - Zhanpeng Gao
- Department of Anatomy and Neurobiology, School of Medicine, Shandong University, Jinan, Shandong, China
| | - Hongyu Liu
- Institute of Sport and Exercise Medicine, North University of China, Taiyuan, China
| | - Zhen Wang
- Department of Cardiology, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Jinhao Sun
- Department of Anatomy and Neurobiology, School of Medicine, Shandong University, Jinan, Shandong, China
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Jeong JK, Dow SA, Young CN. Sensory Circumventricular Organs, Neuroendocrine Control, and Metabolic Regulation. Metabolites 2021; 11:metabo11080494. [PMID: 34436435 PMCID: PMC8402088 DOI: 10.3390/metabo11080494] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/13/2021] [Accepted: 07/27/2021] [Indexed: 11/16/2022] Open
Abstract
The central nervous system is critical in metabolic regulation, and accumulating evidence points to a distributed network of brain regions involved in energy homeostasis. This is accomplished, in part, by integrating peripheral and central metabolic information and subsequently modulating neuroendocrine outputs through the paraventricular and supraoptic nucleus of the hypothalamus. However, these hypothalamic nuclei are generally protected by a blood-brain-barrier limiting their ability to directly sense circulating metabolic signals—pointing to possible involvement of upstream brain nuclei. In this regard, sensory circumventricular organs (CVOs), brain sites traditionally recognized in thirst/fluid and cardiovascular regulation, are emerging as potential sites through which circulating metabolic substances influence neuroendocrine control. The sensory CVOs, including the subfornical organ, organum vasculosum of the lamina terminalis, and area postrema, are located outside the blood-brain-barrier, possess cellular machinery to sense the metabolic interior milieu, and establish complex neural networks to hypothalamic neuroendocrine nuclei. Here, evidence for a potential role of sensory CVO-hypothalamic neuroendocrine networks in energy homeostasis is presented.
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Affiliation(s)
| | | | - Colin N. Young
- Correspondence: ; Tel.: +1-202-994-9575; Fax: +1-202-994-287
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Oe H, Yoshiki H, Zha X, Kobayashi H, Aoki Y, Ito H, Yokoyama O. Urinary reabsorption in the rat kidney by anticholinergics. Sci Rep 2021; 11:9191. [PMID: 33911165 PMCID: PMC8080556 DOI: 10.1038/s41598-021-88738-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 04/12/2021] [Indexed: 11/25/2022] Open
Abstract
Anticholinergics, therapeutic agents for overactive bladder, are clinically suggested to reduce urine output. We investigated whether this effect is due to bladder or kidney urine reabsorption. Various solutions were injected into the bladder of urethane-anesthetized SD rats. The absorption rate for 2 h was examined following the intravenous administration of the anticholinergics imidafenacin (IM), atropine (AT), and tolterodine (TO). The bilateral ureter was then canulated and saline was administered to obtain a diuretic state. Anticholinergics or 1-deamino-[8-D-arginine]-vasopressin (dDAVP) were intravenously administered. After the IM and dDAVP administrations, the rat kidneys were immunostained with AQP2 antibody, and intracellular cAMP was measured. The absorption rate was ~ 10% of the saline injected into the bladder and constant even when anticholinergics were administered. The renal urine among peaked 2 h after the saline administration. Each of the anticholinergics significantly suppressed the urine production in a dose-dependent manner, as did dDAVP. IM and dDAVP increased the intracellular cAMP levels and caused the AQP2 molecule to localize to the collecting duct cells' luminal side. The urinary reabsorption mechanism through the bladder epithelium was not activated by anticholinergic administration. Thus, anticholinergics suppress urine production via an increase in urine reabsorption in the kidneys' collecting duct cells via AQP2.
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Affiliation(s)
- Hideki Oe
- Department of Urology, Faculty of Medical Science, University of Fukui, 23-3 Matsuokashimoaizuki, Eiheiji-cho, Yoshida-gun, Fukui, 910-1193, Japan.
| | - Hatsumi Yoshiki
- Department of Urology, Faculty of Medical Science, University of Fukui, 23-3 Matsuokashimoaizuki, Eiheiji-cho, Yoshida-gun, Fukui, 910-1193, Japan
| | - Xinmin Zha
- Department of Urology, Faculty of Medical Science, University of Fukui, 23-3 Matsuokashimoaizuki, Eiheiji-cho, Yoshida-gun, Fukui, 910-1193, Japan
| | - Hisato Kobayashi
- Department of Urology, Faculty of Medical Science, University of Fukui, 23-3 Matsuokashimoaizuki, Eiheiji-cho, Yoshida-gun, Fukui, 910-1193, Japan
| | - Yoshitaka Aoki
- Department of Urology, Faculty of Medical Science, University of Fukui, 23-3 Matsuokashimoaizuki, Eiheiji-cho, Yoshida-gun, Fukui, 910-1193, Japan
| | - Hideaki Ito
- Department of Urology, Faculty of Medical Science, University of Fukui, 23-3 Matsuokashimoaizuki, Eiheiji-cho, Yoshida-gun, Fukui, 910-1193, Japan
| | - Osamu Yokoyama
- Department of Urology, Faculty of Medical Science, University of Fukui, 23-3 Matsuokashimoaizuki, Eiheiji-cho, Yoshida-gun, Fukui, 910-1193, Japan
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Nagano H, Sobue Y, Matsuyama H, Saito S, Sakai H, Alom F, Tanahashi Y, Ishii T, Unno T. Muscarinic M 2 receptor promotes vasopressin synthesis in mice supraoptic nuclei. J Endocrinol 2018; 237:207-216. [PMID: 29563233 DOI: 10.1530/joe-17-0630] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 03/21/2018] [Indexed: 11/08/2022]
Abstract
Muscarinic acetylcholine receptors have been suggested to be implicated in arginine-vasopressin secretion because intracerebroventricular muscarinic agonist administration induces arginine-vasopressin release into the circulation. Although which subtype is involved in the regulation of arginine-vasopressin secretion is unclear, M2 receptors have been reported to be highly expressed in the hypothalamus. In the present study, M2 receptor-knockout mice were used to elucidate whether M2 receptor regulates arginine-vasopressin synthesis in the paraventricular nuclei and supraoptic nuclei of the hypothalamus. The number of arginine-vasopressin-immunoreactive neurons in M2 receptor-knockout mice was significantly decreased in the supraoptic nuclei, but not in the paraventricular nuclei compared with wild-type mice. Plasma arginine-vasopressin level in M2 receptor-knockout mice was also significantly lower than in the wild-type mice. Urinary volume and frequency as well as water intake in M2 receptor-knockout mice were significantly higher than those in wild-type mice. The V2 vasopressin receptor expression in kidneys of M2 receptor-knockout mice was comparable with that of wild-type mice, and increased urination in M2 receptor-knockout mice was significantly decreased by administration of desmopressin, a specific V2 receptor agonist, suggesting that V2 receptors in the kidneys of M2 receptor-knockout mice are intact. These results suggest that M2 receptors promote arginine-vasopressin synthesis in the supraoptic nuclei and play a role in the regulation and maintenance of body fluid.
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Affiliation(s)
- Hiroshi Nagano
- Department of Pathogenetic Veterinary ScienceUnited Graduate School of Veterinary Science, Gifu University, Gifu, Japan
| | - Yuki Sobue
- Laboratory of Veterinary PharmacologyFaculty of Applied Biological Science, Gifu University, Gifu, Japan
| | - Hayato Matsuyama
- Laboratory of Veterinary PharmacologyFaculty of Applied Biological Science, Gifu University, Gifu, Japan
| | - Shoichiro Saito
- Laboratory of Veterinary AnatomyFaculty of Applied Biological Science, Gifu University, Gifu, Japan
| | - Hiroki Sakai
- Laboratory of Veterinary PathologyFaculty of Applied Biological Science, Gifu University, Gifu, Japan
| | - Firoj Alom
- Department of Pathogenetic Veterinary ScienceUnited Graduate School of Veterinary Science, Gifu University, Gifu, Japan
| | - Yasuyuki Tanahashi
- Department of Animal Medical SciencesFaculty of Life Science, Kyoto Sangyo University, Kyoto, Japan
| | - Toshiaki Ishii
- Department of Basic Veterinary MedicineObihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan
| | - Toshihiro Unno
- Laboratory of Veterinary PharmacologyFaculty of Applied Biological Science, Gifu University, Gifu, Japan
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Lutaif NA, Gontijo LM, Figueiredo JF, Gontijo JAR. Altered urinary sodium excretion response after central cholinergic and adrenergic stimulation of adult spontaneously hypertensive rats. J Physiol Sci 2015; 65:265-75. [PMID: 25690463 PMCID: PMC10717338 DOI: 10.1007/s12576-015-0364-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 02/04/2015] [Indexed: 11/24/2022]
Abstract
In this study, we hypothesized that blunting of the natriuresis response to intracerebroventricularly (i.c.v.) microinjected cholinergic and adrenergic agonists is involved in the development of hypertension in spontaneously hypertensive rats (SHR). We evaluated the effect of i.c.v. injection of cholinergic and noradrenergic agonists, at increasing concentrations, and of muscarinic cholinergic and α1 and α2-adrenoceptor antagonists on blood pressure and urinary sodium handling in SHR, compared with age-matched Wistar Kyoto rats (WR). We confirmed that CCh and NE microinjected into the lateral ventricle (LV) of conscious rats leads to enhanced natriuresis. This response was associated with increased proximal and post-proximal sodium excretion accompanied by an unchanged rate of glomerular filtration. We showed that cholinergic-induced natriuresis in WR and SHR was attenuated by previous i.c.v. administration of atropine and was significantly lower in the hypertensive strain than in WR. In both groups the natriuretic effect of injection of noradrenaline into the LV was abolished by previous local injection of an α1-adrenoceptor antagonist (prazosin). Conversely, LV α2-adrenoceptor antagonist (yohimbine) administration potentiated the action of noradrenaline. The LV yohimbine pretreatment normalized urinary sodium excretion in SHR compared with age-matched WR. In conclusion, these are, as far as we are aware, the first results showing the importance of interaction of central cholinergic and/or noradrenergic receptors in the pathogenesis of spontaneous hypertension. These experiments also provide good evidence of the existence of a central adrenergic mechanism consisting of α1 and α2-adrenoceptors which works antagonistically on regulation of renal sodium excretion.
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Affiliation(s)
- Nelson A. Lutaif
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidro-Salino, Núcleo de Medicina e Cirurgia Experimental, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP 13083-970 Brazil
| | - Lívia M. Gontijo
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidro-Salino, Núcleo de Medicina e Cirurgia Experimental, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP 13083-970 Brazil
| | - José F. Figueiredo
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidro-Salino, Núcleo de Medicina e Cirurgia Experimental, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP 13083-970 Brazil
| | - José A. R. Gontijo
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidro-Salino, Núcleo de Medicina e Cirurgia Experimental, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP 13083-970 Brazil
- Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP 13083-887 Brazil
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Urzedo-Rodrigues LS, Ferreira HS, Santana RC, Luz CP, Perrone CF, Fregoneze JB. Blockade of 5-Ht3 receptors in the septal area increases Fos expression in selected brain areas. Auton Neurosci 2014; 181:55-68. [DOI: 10.1016/j.autneu.2014.01.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 12/02/2013] [Accepted: 01/08/2014] [Indexed: 02/07/2023]
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Shi L, Mao C, Zeng F, Zhu L, Xu Z. Central cholinergic mechanisms mediate swallowing, renal excretion, and c-fos expression in the ovine fetus near term. Am J Physiol Regul Integr Comp Physiol 2008; 296:R318-25. [PMID: 19005017 DOI: 10.1152/ajpregu.90632.2008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fetal swallowing and renal metabolism contribute importantly to amniotic and body fluid homeostasis. To determine central cholinergic modulation of swallowing activity and renal excretion associated with neural activity, we examined the effects of intracerebroventricular injection of carbachol, a cholinergic agonist, in ovine fetuses at 0.9 gestation. Fetuses were chronically prepared with thyrohyoid, nuchal and thoracic esophagus, and diaphragm electromyogram electrodes, as well as lateral ventricle and vascular catheters. Electrodes were also implanted on the parietal dura for determination of fetal electrocorticogram (ECoG). After 5 days of recovery, fetal swallowing, ECoG, and urine output were monitored during basal period and the experimental period following intracerebroventricular injection of 0.9% NaCl as the control (n = 5) or carbachol (3 microg/kg, n = 5). Central carbachol did not significantly change fetal low voltage (LV) and high voltage (HV) ECoG temporal distributions. However, swallowing activity during LV ECoG was elevated significantly after intracerebroventricular carbachol. Associated with the swallowing activation, c-fos immunoreactivity in the putative dipsogenic center, subfornical organ, was enhanced significantly. The fetal urine flow rate and renal Na+, K+, and Cl(-) excretion were markedly increased following intracerebroventricular carbachol and sustained at the high level for at least 2 h. The results indicate that the central cholinergic mechanism is established and functional in regulation of fetal behavior and renal excretion at least at 0.9 gestation, which plays an important role in maintenance of fetal body fluid homeostasis.
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Affiliation(s)
- Lijun Shi
- Department of Human Sport Science, Beijing Sport University, Beijing, China
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Mao C, Yuan X, Zhang H, Lv J, Guan J, Miao L, Chen L, Zhang Y, Zhang L, Xu Z. The effect of prenatal nicotine on mRNA of central cholinergic markers and hematological parameters in rat fetuses. Int J Dev Neurosci 2008; 26:467-75. [PMID: 18407449 DOI: 10.1016/j.ijdevneu.2008.02.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2007] [Revised: 02/24/2008] [Accepted: 02/25/2008] [Indexed: 11/28/2022] Open
Abstract
A number of studies have demonstrated the influence of nicotine on fetal development. This study determined the expression of choline acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT), and high-affinity choline transporter (CHT1) in the forebrain and hindbrain following chronic prenatal nicotine exposure in the rat fetus (maternal rats were subcutaneously injected with nicotine at different gestation periods). We also measured the effect of chronic nicotine exposure on fetal blood pO(2), pCO(2), pH, Na(+) and K(+) concentrations, as well as lactic acid levels. Maternal nicotine exposure during pregnancy was associated with a decrease in fetal pO(2) coupled with a significant increase in pCO(2) and lactic acid as well as restricted fetal growth. Additionally, maternal nicotine administration also reduced ChAT, VAChT, and CHT1 mRNA levels in the fetal brain. Nicotine-induced fetal hypoxic responses and reduced cholinergic marker expression in the brain were more severe when nicotine was started in early gestation. Our results provide new information about the effects of repeated exposure to nicotine in utero on the expression of central ChAT, VAChT, and CHT1 in the rat fetus. These results indicate that repeated hypoxic episodes or/and a direct effect of nicotine on the central cholinergic system during pregnancy may contribute to brain developmental problems in fetal origin.
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Affiliation(s)
- Caiping Mao
- Perinatal Biology Center, Soochow University School of Medicine, Suzhou, China
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Prenatal exposure to nicotine with associated in utero hypoxia decreased fetal brain muscarinic mRNA in the rat. Brain Res 2007; 1189:43-50. [PMID: 18053972 DOI: 10.1016/j.brainres.2007.10.089] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Revised: 10/23/2007] [Accepted: 10/31/2007] [Indexed: 11/20/2022]
Abstract
Prenatal exposure to nicotine can be associated with fetal abnormal development and brain damage. This study determined the effect of administration of nicotine with associated in utero hypoxia in maternal rats from early, middle, and late gestation on fetal blood hemoglobin, and expression of cholinergic receptor subtypes in the fetal brain. Our results demonstrated that maternal subcutaneous nicotine from the early gestation increased fetal hemoglobin and hematocrit, associated with reduction of PO(2). Although exposure to nicotine during late gestation had no effects on fetal brain weight, nicotine administration from the early gestation significantly decreased fetal brain muscarinic receptor (M1, M2, M3, and M4) mRNA expression, associated with restricted brain growth. Nicotine-altered muscarinic receptor subtype expression in the fetal forebrain and hindbrain showed regional differences. In addition, there were gestational differences for fetal brain muscarinic suppression by prenatal nicotine. Together, the results demonstrate that nicotine-induced in utero hypoxia is associated with poor development of muscarinic receptors in the fetal brain and restricted brain growth, and that either prolonged prenatal exposure to nicotine or critical "window" period for the brain development during pregnancy may play a role in prenatal nicotine-induced fetal muscarinic-receptor deficiency in the fetal brain.
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Shibata O, Tanaka J, Nomura M. Non-NMDA glutamatergic receptors modulate acetylcholine release in the rat subfornical organ area. Auton Neurosci 2006; 124:96-102. [PMID: 16458077 DOI: 10.1016/j.autneu.2005.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2005] [Revised: 11/10/2005] [Accepted: 12/11/2005] [Indexed: 10/25/2022]
Abstract
The present study was designed to examine whether glutamatergic receptor mechanisms modulate the release of acetylcholine (ACh) in the region of the subfornical organ (SFO) using intracerebral microdialysis methods in freely moving rats. Perfusion of either non-N-methyl-d-aspartate (NMDA) agonist quisqualic acid (QA, 50 microM) or kainic acid (KA, 50 microM) through the microdialysis probe significantly enhanced the ACh release in the SFO area. Local perfusion of the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 10 and 50 microM) did not change the basal release of ACh. CNQX (10 microM) administered together with either QA (50 microM) or KA (50 microM) in the SFO area antagonized the stimulant effect of the agonists on the ACh release. In urethane-anesthetized rats, repetitive electrical stimulation (500 microA, 10 Hz) of the medial septum (MS) significantly increased dialysate ACh concentrations in the region of the SFO. The increase in the ACh release elicited by the MS stimulation was significantly potentiated by perfusion of QA (50 microM), and the QA-induced potentiation was prevented by CNQX (10 microM) treated together with QA. These results show that the glutamatergic synaptic inputs enhance the ACh release in the SFO area through non-NMDA receptors. The data further suggest that the septal cholinergic inputs to the SFO area are potentiated by non-NMDA receptor mechanisms.
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Affiliation(s)
- Osayuki Shibata
- Department of Physiology, Saitama Medical School, Moroyama-cho, Iruma-gun, Saitama 350-0495, Japan
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12
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Tanaka J. Activation of cholinergic pathways from the septum to the subfornical organ area under hypovolemic condition in rats. Brain Res Bull 2003; 61:497-504. [PMID: 13679248 DOI: 10.1016/s0361-9230(03)00186-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In urethane-anesthetized rats, extracellular concentrations of acetylcholine (ACh) in the region of the subfornical organ (SFO) in response to electrical stimulation of the septum and hypovolemia were monitored with in vivo microdialysis methods. Repetitive electrical stimulation (500 microA, 5-20 Hz) of the medial septum significantly increased dialysate ACh concentrations in the region of the SFO. Non-hypotensive hypovolemia caused by subcutaneous administration of polyethylene glycol (PEG, 30%, 5 ml) elicited significantly increased ACh levels in the region of the SFO. The hypovolemia-induced ACh release was attenuated by microinjection of the local anesthetic lidocaine (2%, 0.2 microl) into the medial septum. These results suggest that septal cholinergic pathways to the SFO area may be activated under the hypovolemic condition.
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Affiliation(s)
- Junichi Tanaka
- Department of Curriculum, Teaching and Memory, Naruto University of Education, Takashima, Naruto-cho, Naruto 772-8502, Tokushima, Japan.
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Honda E, Ono K, Toyono T, Kawano H, Masuko S, Inenaga K. Activation of muscarinic receptors in rat subfornical organ neurones. J Neuroendocrinol 2003; 15:770-7. [PMID: 12834438 DOI: 10.1046/j.1365-2826.2003.01057.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cholinergic muscarinic inputs to subfornical organ (SFO) neurones in rats were studied using histochemical, molecular-biological and electrophysiological techniques. Neurones in the medial septum and the diagonal band (MS-DBB) were retrogradely labelled by a tracer wheat germ agglutinin-conjugated horseradish peroxidase-colloidal gold complex injected into the SFO. Some in the MS-DBB were double-labelled by choline acetyltransferase (ChAT) antibody. Many ChAT-immunoreactive fibres were observed in the SFO. M3 muscarinic receptor subtype-like immunoreactivity, detected using a polyclonal antiserum, was observed in the SFO. In slice preparations, muscarine induced inward currents in a dose-related manner. The inward currents were suppressed by the relatively M3 muscarinic receptor selective antagonist 4-diphenylacetoxy-N-methylpiredine methiodide. In the whole-cell current mode, muscarine depolarized the membrane with increased frequency of action potentials. Reverse transcriptase-polymerase chain reaction showed the presence of M2-M5 receptor mRNA in the SFO tissues. These results suggest that the SFO receives cholinergic muscarinic synaptic inputs from the MS-DBB. Acetylcholine postsynaptically activates and depolarizes neurones in the SFO partly through specific muscarinic receptors, including M3 receptor subtypes.
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Affiliation(s)
- E Honda
- Department of Physiology, Kyushu Dental College, Kokurakitaku, Kitakyushu, Japan
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Rowland NE, Farnbauch LJ, Robertson KL. Brain muscarinic receptor subtypes mediating water intake and Fos following cerebroventricular administration of bethanecol in rats. Psychopharmacology (Berl) 2003; 167:174-9. [PMID: 12655462 DOI: 10.1007/s00213-003-1394-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2002] [Accepted: 12/21/2002] [Indexed: 11/27/2022]
Abstract
RATIONALE The brain regions and receptor subtypes involved in water intake following central cholinergic stimulation have been incompletely characterized. OBJECTIVES To examine whether drinking and brain Fos-immunoreactivity (ir) induced in rats by central administration of bethanecol is reversed by either the preferential M1 antagonist pirenzepine, the M3 antagonist 4-DAMP, or their combination. METHODS Male Sprague-Dawley rats were surgically implanted with cerebroventricular cannulae. The muscarinic agonist, bethanecol was used as the dipsogenic agent. Either nonselective (atropine) or selective muscarinic receptor antagonists were injected together with bethanecol to determine blockade of drinking. In parallel studies, Fos-ir was assessed in discrete brain regions. RESULTS Bethanecol-induced drinking was completely blocked by atropine or by a combination of pirenzepine and 4-DAMP; these latter antagonists alone produced sub-total inhibition of drinking. In contrast, water intake induced by angiotensin II was unaffected by combination of pirenzepine and 4-DAMP. Fos-ir was induced by bethanecol in many brain regions previously implicated in body fluid regulation, including subfornical organ and the magnocellular supraoptic and paraventricular hypothalamic nuclei. Induced Fos-ir was substantially but not completely prevented by co-injection of either pirenzepine or 4-DAMP, but their combination did not seem markedly more effective than either alone. CONCLUSIONS Drinking induced by brain muscarinic receptor stimulation seems to proceed by a combination of M1 and M3 receptor subtypes. Drinking induced by angiotensin II occurs independently of this mechanism. Fos-ir induced in fluid-related brain regions by bethanecol either uses additional receptor type(s) or is less easily blocked than drinking behavior.
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Affiliation(s)
- Neil E Rowland
- Department of Psychology, University of Florida, P.O. Box 112250, Gainesville, FL 32611-2250, USA.
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Xu Z, Torday J, Yao J. Functional and anatomic relationship between cholinergic neurons in the median preoptic nucleus and the supraoptic cells. Brain Res 2003; 964:171-8. [PMID: 12576177 DOI: 10.1016/s0006-8993(02)03800-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The median preoptic nucleus (MePO) has been suggested to be an important area in the brain for the regulation of vasopressin (VP) release under the condition of osmotic stimulation. Fos immunoreactivity (Fos-ir), choline acetyltransferase (ChAT) immunoreactivity and retrograde labeling with fluoro-gold were used in this study to determine whether cholinergic neurons in the MePO can be activated by hypertonic NaCl, and to characterize the specific MePO cells that have anatomic projections to the supraoptic nuclei (SON). The results showed that c-fos expression specifically induced by hypertonic NaCl was found in the ChAT cells of the MePO. A retrograde tracing experiment demonstrated that the MePO neurons projecting to the SON were cholinergic. In addition, hypertonic saline-induced Fos-ir was colocalized with the MePO neurons back labeled with fluoro-gold from the SON. Together, these data provide evidence that the MePO cholinergic neurons are activated by osmotic stimulation, and suggest that cholinergic cells in the MePO are functionally important in the control of the SON neurons under the condition of hypertonic stimulation.
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Affiliation(s)
- Zhice Xu
- Perinatal Research Laboratory, Department of Obstetrics and Gynecology, Harbor-UCLA Medical Center, Research and Education Institute, 1124 W. Carson St., RB-1, Torrance, CA 90502, USA.
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