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Callera JC, De Luca LA, Menani JV. Involvement of V1-type vasopressin receptors on NaCl intake by hyperosmotic rats treated with muscimol in the lateral parabrachial nucleus. Neurosci Lett 2022; 778:136601. [DOI: 10.1016/j.neulet.2022.136601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/25/2022] [Accepted: 03/26/2022] [Indexed: 11/29/2022]
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NODA M, MATSUDA T. Central regulation of body fluid homeostasis. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2022; 98:283-324. [PMID: 35908954 PMCID: PMC9363595 DOI: 10.2183/pjab.98.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Extracellular fluids, including blood, lymphatic fluid, and cerebrospinal fluid, are collectively called body fluids. The Na+ concentration ([Na+]) in body fluids is maintained at 135-145 mM and is broadly conserved among terrestrial animals. Homeostatic osmoregulation by Na+ is vital for life because severe hyper- or hypotonicity elicits irreversible organ damage and lethal neurological trauma. To achieve "body fluid homeostasis" or "Na homeostasis", the brain continuously monitors [Na+] in body fluids and controls water/salt intake and water/salt excretion by the kidneys. These physiological functions are primarily regulated based on information on [Na+] and relevant circulating hormones, such as angiotensin II, aldosterone, and vasopressin. In this review, we discuss sensing mechanisms for [Na+] and hormones in the brain that control water/salt intake behaviors, together with the responsible sensors (receptors) and relevant neural pathways. We also describe mechanisms in the brain by which [Na+] increases in body fluids activate the sympathetic neural activity leading to hypertension.
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Affiliation(s)
- Masaharu NODA
- Homeostatic Mechanism Research Unit, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
- Correspondence should be addressed to: Homeostatic Mechanism Research Unit, Institute of Innovative Research, Tokyo Institute of Technology, Nagatsuta-cho 4259, Midori-ku, Yokohama, Kanagawa 226-8503, Japan (e-mail: )
| | - Takashi MATSUDA
- Homeostatic Mechanism Research Unit, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
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Yokota T, Katakura N, Morita T, Matsunaga T, Hiraba K. Two neuronal groups for NaCl with differential taste response properties and topographical distributions in the rat parabrachial nucleus. Physiol Rep 2020; 8:e14443. [PMID: 32441441 PMCID: PMC7243197 DOI: 10.14814/phy2.14443] [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: 08/28/2019] [Revised: 12/23/2019] [Accepted: 01/04/2020] [Indexed: 11/24/2022] Open
Abstract
It is crucial for animals to discriminate between palatable (safe) and aversive (toxic) tastants. The mechanisms underlying neuronal discrimination of taste stimuli remain unclear. We examined relations between taste response properties (spike counts, response duration, and coefficient of variation [CV]) and location of taste-sensitive neurons in the pontine parabrachial nucleus (PBN). Extracellular single units' activity in the PBN of Wistar rats was recorded using multibarrel glass micropipettes under urethane anesthesia. Forty taste-sensitive neurons were classified as NaCl (N)-best (n = 15), NaCl/HCl (NH)-best (n = 14), HCl (H)-best (n = 8), and sucrose (S)-best (n = 3) neurons. The net response to NaCl (15.2 ± 2.3 spikes/s) among the N-best neurons was significantly larger than that among the NH-best (4.5 ± 0.8 spikes/s) neurons. The response duration (4.5 ± 0.2 s) of the N-best neurons to NaCl was significantly longer than that of the NH-best (2.2 ± 0.3 s) neurons. These differences in the spike counts and the response durations between the two neuronal types in the PBN were similar to that previously reported in the rostral nucleus of the solitary tract (rNST). The CVs in the N-best and the NH-best neurons were significantly smaller in the PBN than those in the rNST. Histologically, most N-best neurons (12/13, 92%) were localized to the medial region, while NH-best neurons (11/13, 85%) were primarily found within the brachium conjunctivum. These results suggest that NaCl-specific taste information is transmitted by two distinct neuronal groups (N-best and NH-best), with different taste properties and locations within rNST to PBN tractography. Future studies on the higher order nuclei for taste could reveal more palatable and aversive taste pathways.
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Affiliation(s)
- Tatsuko Yokota
- Department of PhysiologySchool of DentistryAichi‐Gakuin UniversityNagoyaJapan
| | - Nubuo Katakura
- Department of PhysiologySchool of DentistryAichi‐Gakuin UniversityNagoyaJapan
| | - Takumi Morita
- Department of PhysiologySchool of DentistryAichi‐Gakuin UniversityNagoyaJapan
| | - Tomoko Matsunaga
- Department of PhysiologySchool of DentistryAichi‐Gakuin UniversityNagoyaJapan
| | - Katsunari Hiraba
- Department of PhysiologySchool of DentistryAichi‐Gakuin UniversityNagoyaJapan
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Anesio A, Barbosa SP, De Luca LA, de Paula PM, Colombari DSA, Colombari E, Andrade CAF, Menani JV. Central muscarinic and LPBN mechanisms on sodium intake. Brain Res Bull 2018; 144:14-20. [PMID: 30391542 DOI: 10.1016/j.brainresbull.2018.10.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 10/25/2018] [Accepted: 10/30/2018] [Indexed: 11/28/2022]
Abstract
Central cholinergic activation stimulates water intake, but also NaCl intake when the inhibitory mechanisms are blocked with injections of moxonidine (α2 adrenergic/imidazoline agonist) into the lateral parabrachial nucleus (LPBN). In the present study, we investigated the involvement of central M1 and M2 muscarinic receptors on NaCl intake induced by pilocarpine (non-selective muscarinic agonist) intraperitoneally combined with moxonidine into the LPBN or by muscimol (GABAA agonist) into the LPBN. Male Holtzman rats with stainless steel cannulas implanted bilaterally in the LPBN and in the lateral ventricle were used. Pirenzepine (M1 muscarinic antagonist, 1 nmol/1 μl) or methoctramine (M2 muscarinic antagonist, 50 nmol/1 μL) injected intracerebroventricularly (i.c.v.) reduced 0.3 M NaCl and water intake in rats treated with pilocarpine (0.1 mg/100 g of body weight) injected intraperitoneally combined with moxonidine (0.5 nmol/0.2 μL) into the LPBN. In rats treated with muscimol (0.5 nmol/0.2 μL) into the LPBN, methoctramine i.c.v. also reduced 0.3 M NaCl and water intake, however, pirenzepine produced no effect. The results suggest that M1 and M2 muscarinic receptors activate central pathways involved in the control of water and sodium intake that are under the influence of the LPBN inhibitory mechanisms.
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Affiliation(s)
- Augusto Anesio
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - Silas Pereira Barbosa
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - Laurival A De Luca
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - Patrícia Maria de Paula
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - Débora S A Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - Eduardo Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - Carina A F Andrade
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - José V Menani
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil.
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Töle J, Stolzenburg A, Tyree SM, Stähler F, Meyerhof W. Tastant-Evoked Arc Expression in the Nucleus of the Solitary Tract and Nodose/Petrosal Ganglion of the Mouse Is Specific for Bitter Compounds. Chem Senses 2018. [PMID: 29514200 DOI: 10.1093/chemse/bjy017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Despite long and intense research, some fundamental questions regarding representation of taste information in the brain still remain unanswered. This might in part be due to shortcomings of the established methods that limit the researcher either to thorough characterization of few elements or to analyze the response of the entirety of neurons to only one stimulus. To overcome these restrictions, we evaluate the use of the immediate early gene Arc as a neuronal activity marker in the early neural structures of the taste pathway, the nodose/petrosal ganglion (NPG) and the nucleus of the solitary tract (NTS). Responses of NPG and NTS neurons were limited to substances that taste bitter to humans and are avoided by mice. Arc-expressing cells were concentrated in the rostromedial part of the dorsal NTS suggesting a role in gustatory processing. The use of Arc as a neuronal activity marker has several advantages, primarily the possibility to analyze the response of large numbers of neurons while using more than one stimulus makes Arc an interesting new tool for research in the early stages of taste processing.
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Affiliation(s)
- Jonas Töle
- Department of Molecular Genetics, German Institute of Human Nutrition Potsdam-Rehbrücke, Arthur-Scheunert-Allee, Nuthetal, Germany
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Lateral parabrachial nucleus and opioid mechanisms of the central nucleus of the amygdala in the control of sodium intake. Behav Brain Res 2017; 316:11-17. [DOI: 10.1016/j.bbr.2016.08.035] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 08/11/2016] [Accepted: 08/16/2016] [Indexed: 11/21/2022]
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Satiation and re-intake after partial withdrawal of gastric food contents: A dissociation effect in external lateral parabrachial lesioned rats. Brain Res Bull 2016; 127:126-133. [DOI: 10.1016/j.brainresbull.2016.09.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 09/06/2016] [Accepted: 09/09/2016] [Indexed: 11/19/2022]
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CNS sites activated by renal pelvic epithelial sodium channels (ENaCs) in response to hypertonic saline in awake rats. Auton Neurosci 2016; 204:35-47. [PMID: 27717709 DOI: 10.1016/j.autneu.2016.09.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 09/17/2016] [Accepted: 09/19/2016] [Indexed: 12/18/2022]
Abstract
In some patients, renal nerve denervation has been reported to be an effective treatment for essential hypertension. Considerable evidence suggests that afferent renal nerves (ARN) and sodium balance play important roles in the development and maintenance of high blood pressure. ARN are sensitive to sodium concentrations in the renal pelvis. To better understand the role of ARN, we infused isotonic or hypertonic NaCl (308 or 500mOsm) into the left renal pelvis of conscious rats for two 2hours while recording arterial pressure and heart rate. Subsequently, brain tissue was analyzed for immunohistochemical detection of the protein Fos, a marker for neuronal activation. Fos-immunoreactive neurons were identified in numerous sites in the forebrain and brainstem. These areas included the nucleus tractus solitarius (NTS), the lateral parabrachial nucleus, the paraventricular nucleus of the hypothalamus (PVH) and the supraoptic nucleus (SON). The most effective stimulus was 500mOsm NaCl. Activation of these sites was attenuated or prevented by administration of benzamil (1μM) or amiloride (10μM) into the renal pelvis concomitantly with hypertonic saline. In anesthetized rats, infusion of hypertonic saline but not isotonic saline into the renal pelvis elevated ARN activity and this increase was attenuated by simultaneous infusion of benzamil or amiloride. We propose that renal pelvic epithelial sodium channels (ENaCs) play a role in activation of ARN and, via central visceral afferent circuits, this system modulates fluid volume and peripheral blood pressure. These pathways may contribute to the development of hypertension.
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Menani JV, De Luca LA, Johnson AK. Role of the lateral parabrachial nucleus in the control of sodium appetite. Am J Physiol Regul Integr Comp Physiol 2014; 306:R201-10. [PMID: 24401989 DOI: 10.1152/ajpregu.00251.2012] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In states of sodium deficiency many animals seek and consume salty solutions to restore body fluid homeostasis. These behaviors reflect the presence of sodium appetite that is a manifestation of a pattern of central nervous system (CNS) activity with facilitatory and inhibitory components that are affected by several neurohumoral factors. The primary focus of this review is on one structure in this central system, the lateral parabrachial nucleus (LPBN). However, before turning to a more detailed discussion of the LPBN, a brief overview of body fluid balance-related body-to-brain signaling and the identification of the primary CNS structures and humoral factors involved in the control of sodium appetite is necessary. Angiotensin II, mineralocorticoids, and extracellular osmotic changes act on forebrain areas to facilitate sodium appetite and thirst. In the hindbrain, the LPBN functions as a key integrative node with an ascending output that exerts inhibitory influences on forebrain regions. A nonspecific or general deactivation of LPBN-associated inhibition by GABA or opioid agonists produces NaCl intake in euhydrated rats without any other treatment. Selective LPBN manipulation of other neurotransmitter systems [e.g., serotonin, cholecystokinin (CCK), corticotrophin-releasing factor (CRF), glutamate, ATP, or norepinephrine] greatly enhances NaCl intake when accompanied by additional treatments that induce either thirst or sodium appetite. The LPBN interacts with key forebrain areas that include the subfornical organ and central amygdala to determine sodium intake. To summarize, a model of LPBN inhibitory actions on forebrain facilitatory components for the control of sodium appetite is presented in this review.
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Affiliation(s)
- Jose V Menani
- Department of Physiology and Pathology, School of Dentistry, Universidade Estadual Paulista, Araraquara, São Paulo, Brazil; and Departments of Psychology, Pharmacology and Health, and Human Physiology and the Cardiovascular Center, University of Iowa, Iowa City, Iowa
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Yokota T, Eguchi K, Hiraba K. Topographical representations of taste response characteristics in the rostral nucleus of the solitary tract in the rat. J Neurophysiol 2013; 111:182-96. [PMID: 24133228 DOI: 10.1152/jn.01031.2012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The rostral nucleus of the solitary tract (rNST) is the first-order taste relay in rats. This study constructed topographical distributions of taste response characteristics (best-stimulus, response magnitude, and taste-tuning) from spike discharges of single neurons in the rNST. The rNST is divided into four subregions along the rostrocaudal (RC) axis, which include r1-r4. We explored single-neuron activity in r1-r3, using multibarreled glass microelectrodes. NaCl (N)-best neurons were localized to the rostral half of r1-r3, while HCl (H)-best and sucrose (S)-best neurons showed a tendency toward more caudal locations. NaCl and HCl (NH)-best neurons were distributed across r2-r3. The mean RC values and Mahalanobis distance indicated a significant difference between the distributions of N-best and NH-best neurons in which N-best neurons were located more rostrally. The region of large responses to NaCl (net response >5 spikes/s) overlapped with the distribution of N-best neurons. The region of large responses to HCl extended widely over r1-r3. The region of large responses to sucrose was in the medial part of r2. The excitatory region (>1 spike/s) for quinine overlapped with that for HCl. Neurons with sharp to moderate tuning were located primarily in r1-r2, while those with broad tuning were located in r2-r3. The robust responses to NaCl in r1-r2 primarily contributed to sharp to moderate taste-tuning. Neurons in r3 tended to have broad tuning, apparently due to small responses to both NaCl and HCl. Therefore, the rNST is spatially organized by neurons with distinct taste response characteristics, suggesting that these neurons serve different functional roles.
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Affiliation(s)
- T Yokota
- Department of Physiology, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan
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Salas M, Torrero C, Rubio L, Regalado M. Effects of perinatal undernutrition on the development of neurons in the rat insular cortex. Nutr Neurosci 2013; 15:20-5. [DOI: 10.1179/1476830512y.0000000014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Kimura EH, De Oliveira LB, Menani JV, Callera JC. Baclofen into the lateral parabrachial nucleus induces hypertonic sodium chloride intake during cell dehydration. Behav Brain Funct 2013; 9:17. [PMID: 23642235 PMCID: PMC3679877 DOI: 10.1186/1744-9081-9-17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 04/23/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Activation of GABA(B) receptors with baclofen into the lateral parabrachial nucleus (LPBN) induces ingestion of water and 0.3 M NaCl in fluid replete rats. However, up to now, no study has investigated the effects of baclofen injected alone or combined with GABA(B) receptor antagonist into the LPBN on water and 0.3 M NaCl intake in rats with increased plasma osmolarity (rats treated with an intragastric load of 2 M NaCl). Male Wistar rats with stainless steel cannulas implanted bilaterally into the LPBN were used. RESULTS In fluid replete rats, baclofen (0.5 nmol/0.2 μl), bilaterally injected into the LPBN, induced ingestion of 0.3 M NaCl (14.3 ± 4.1 vs. saline: 0.2 ± 0.2 ml/210 min) and water (7.1 ± 2.9 vs. saline: 0.6 ± 0.5 ml/210 min). In cell-dehydrated rats, bilateral injections of baclofen (0.5 and 1.0 nmol/0.2 μl) into the LPBN induced an increase of 0.3 M NaCl intake (15.6 ± 5.7 and 21.5 ± 3.5 ml/210 min, respectively, vs. saline: 1.7 ± 0.8 ml/210 min) and an early inhibition of water intake (3.5 ± 1.4 and 6.7 ± 2.1 ml/150 min, respectively, vs. saline: 9.2 ± 1.4 ml/150 min). The pretreatment of the LPBN with 2-hydroxysaclofen (GABA(B) antagonist, 5 nmol/0.2 μl) potentiated the effect of baclofen on 0.3 M NaCl intake in the first 90 min of test and did not modify the inhibition of water intake induced by baclofen in cell-dehydrated rats. Baclofen injected into the LPBN did not affect blood pressure and heart rate. CONCLUSIONS Thus, injection of baclofen into the LPBN in cell-dehydrated rats induced ingestion of 0.3 M NaCl and inhibition of water intake, suggesting that even in a hyperosmotic situation, the blockade of LPBN inhibitory mechanisms with baclofen is enough to drive rats to drink hypertonic NaCl, an effect independent of changes in blood pressure.
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Affiliation(s)
- Everton H Kimura
- Department of Basic Sciences, School of Dentistry, UNESP - Univ. Estadual Paulista, Rodovia Marechal Rondom, km 527, Araçatuba, São Paulo 16018-805, Brazil
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Andrade C, Margatho L, Andrade-Franzé G, De Luca L, Antunes-Rodrigues J, Menani J. Moxonidine into the lateral parabrachial nucleus reduces renal and hormonal responses to cell dehydration. Neuroscience 2012; 208:69-78. [DOI: 10.1016/j.neuroscience.2012.02.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 02/07/2012] [Accepted: 02/07/2012] [Indexed: 11/27/2022]
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Chen K, Yan J, Li J, Lv B, Zhao X. c-Fos expression in rat brainstem following intake of sucrose or saccharin. Front Med 2011; 5:294-301. [PMID: 21964712 DOI: 10.1007/s11684-011-0144-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2011] [Accepted: 06/10/2011] [Indexed: 11/28/2022]
Abstract
To examine whether the activation of brainstem neurons during intake of a sweet tastant is due to orosensory signals or post-ingestive factors, we compared the distribution of c-Fos-like immunoreactivity (c-FLI) in the nucleus of the solitary tract (NST) and parabrachial nucleus (PBN) of brainstem following ingestion of 0.25 Msucrose or 0.005 M saccharin solutions. Immunopositive neurons were localized mainly in the middle zone of the PBN and four rostral-caudal subregions of the NST. Intake of sucrose increased the number of FLI neurons in almost every subnucleus of the PBN (F((2,13)) = 7.610, P = 0.023), in addition to the caudal NST at the level of the area postrema (F((2,13)) = 10.777, P = 0.003) and the NST intermediate zone (F((2,13)) = 7.193, P = 0.014). No significant increase in the number of c-Fos positive neurons was detected in response to saccharin ingestion, although there was a trend towards a modest increase in a few select NST and PBN nuclei. These results suggest that the PBN and NST may be involved in sweet taste perception and modulation of sweet tastant intake, but the significantly enhanced intensity of Fos expression induced by sucrose indicates that PBN/NST neuronal activity is driven by the integrated effects of sweet taste sensation and post-ingestive signals.
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Affiliation(s)
- Ke Chen
- Department of Physiology and Pathophysiology, School of Medicine, Xi'an Jiaotong University, Xi'an, 710061, China
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Changes in taste reactivity to intra-oral hypertonic NaCl after lateral parabrachial injections of an α2-adrenergic receptor agonist. Physiol Behav 2011; 104:702-8. [DOI: 10.1016/j.physbeh.2011.07.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 07/13/2011] [Accepted: 07/14/2011] [Indexed: 11/17/2022]
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Bruijnzeel AW, Corrie LW, Rogers JA, Yamada H. Effects of insulin and leptin in the ventral tegmental area and arcuate hypothalamic nucleus on food intake and brain reward function in female rats. Behav Brain Res 2011; 219:254-64. [PMID: 21255613 PMCID: PMC3062744 DOI: 10.1016/j.bbr.2011.01.020] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 01/07/2011] [Accepted: 01/11/2011] [Indexed: 11/21/2022]
Abstract
There is evidence for a role of insulin and leptin in food intake, but the effects of these adiposity signals on the brain reward system are not well understood. Furthermore, the effects of insulin and leptin on food intake in females are underinvestigated. These studies investigated the role of insulin and leptin in the ventral tegmental area (VTA) and the arcuate hypothalamic nucleus (Arc) on food intake and brain reward function in female rats. The intracranial self-stimulation procedure was used to assess the effects of insulin and leptin on the reward system. Elevations in brain reward thresholds are indicative of a decrease in brain reward function. The bilateral administration of leptin into the VTA (15-500 ng/side) or Arc (15-150 ng/side) decreased food intake for 72 h. The infusion of leptin into the VTA or Arc resulted in weight loss during the first 48 (VTA) or 24 h (Arc) after the infusions. The administration of insulin (0.005-5 mU/side) into the VTA or Arc decreased food intake for 24 h but did not affect body weights. The bilateral administration of low, but not high, doses of leptin (15 ng/side) or insulin (0.005 mU/side) into the VTA elevated brain reward thresholds. Neither insulin nor leptin in the Arc affected brain reward thresholds. These studies suggest that a small increase in leptin or insulin levels in the VTA leads to a decrease in brain reward function. A relatively large increase in insulin or leptin levels in the VTA or Arc decreases food intake.
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Affiliation(s)
- Adrie W Bruijnzeel
- Department of Psychiatry, McKnight Brain Institute, University of Florida, 100 S. Newell Dr., Gainesville, FL 32610, USA.
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Stein MK, Loewy AD. Area postrema projects to FoxP2 neurons of the pre-locus coeruleus and parabrachial nuclei: brainstem sites implicated in sodium appetite regulation. Brain Res 2010; 1359:116-27. [PMID: 20816675 PMCID: PMC2955772 DOI: 10.1016/j.brainres.2010.08.085] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 08/24/2010] [Accepted: 08/25/2010] [Indexed: 12/28/2022]
Abstract
The area postrema (AP) is a circumventricular organ located in the dorsal midline of the medulla. It functions as a chemosensor for blood-borne peptides and solutes, and converts this information into neural signals that are transmitted to the nucleus tractus solitarius (NTS) and parabrachial nucleus (PB). One of its NTS targets in the rat is the aldosterone-sensitive neurons which contain the enzyme 11 β-hydroxysteroid dehydrogenase type 2 (HSD2). The HSD2 neurons are part of a central network involved in sodium appetite regulation, and they innervate numerous brain sites including the pre-locus coeruleus (pre-LC) and PB external lateral-inner (PBel-inner) cell groups of the dorsolateral pons. Both pontine cell groups express the transcription factor FoxP2 and become c-Fos activated following sodium depletion. Because the AP is a component in this network, we wanted to determine whether it also projects to the same sites as the HSD2 neurons. By using a combination of anterograde axonal and retrograde cell body tract-tracing techniques in individual rats, we show that the AP projects to FoxP2 immunoreactive neurons in the pre-LC and PBel-inner. Thus, the AP sends a direct projection to both the first-order medullary (HSD2 neurons of the NTS) and the second-order dorsolateral pontine neurons (pre-LC and PB-el inner neurons). All three sites transmit information related to systemic sodium depletion to forebrain sites and are part of the central neural circuitry that regulates the complex behavior of sodium appetite.
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Affiliation(s)
- Matthew K. Stein
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Arthur D. Loewy
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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Lesions in the central amygdala impair sodium intake induced by the blockade of the lateral parabrachial nucleus. Brain Res 2010; 1332:57-64. [DOI: 10.1016/j.brainres.2010.03.055] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 03/13/2010] [Accepted: 03/15/2010] [Indexed: 11/22/2022]
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Andrade-Franzé G, Andrade C, De Luca L, De Paula P, Menani J. Lateral parabrachial nucleus and central amygdala in the control of sodium intake. Neuroscience 2010; 165:633-41. [DOI: 10.1016/j.neuroscience.2009.11.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Revised: 10/08/2009] [Accepted: 11/04/2009] [Indexed: 10/20/2022]
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20
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Godino A, Margatho LO, Caeiro XE, Antunes-Rodrigues J, Vivas L. Activation of lateral parabrachial afferent pathways and endocrine responses during sodium appetite regulation. Exp Neurol 2010; 221:275-84. [DOI: 10.1016/j.expneurol.2009.11.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 10/05/2009] [Accepted: 11/03/2009] [Indexed: 11/29/2022]
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De la Torre ML, Agüero Á. The role of the medial-external subnucleus of the medial parabrachial nucleus in hypertonic NaCl-induced concurrent and delayed-sequential flavor avoidance learning. Exp Brain Res 2009; 194:207-18. [DOI: 10.1007/s00221-008-1686-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Accepted: 12/06/2008] [Indexed: 10/21/2022]
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22
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De Oliveira L, De Luca L, Menani J. Opioid activation in the lateral parabrachial nucleus induces hypertonic sodium intake. Neuroscience 2008; 155:350-8. [DOI: 10.1016/j.neuroscience.2008.06.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2008] [Revised: 04/26/2008] [Accepted: 06/03/2008] [Indexed: 11/17/2022]
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23
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The role of the dorsal-most part of the lateral parabrachial nucleus in the processing of hypertonic NaCl using different conditioned flavor avoidance paradigms. Exp Brain Res 2008; 186:481-91. [PMID: 18193413 DOI: 10.1007/s00221-007-1250-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Accepted: 12/05/2007] [Indexed: 10/22/2022]
Abstract
The parabrachial nucleus (PBN) has been strongly associated with taste aversion learning (TAL) acquisition. Independent of its suggested associative functions, this brain stem centre plays a key role in the sensorial processing of both gustatory and visceral information. The sensory visceral functions have been attributed to the lateral area of the PBN (PBNl) but, recently, it has been proposed that within this area a form of anatomical and functional segregation may also exist, determined by factors such as, the learning paradigm used, the nature of aversive agent used, or the route chosen for the administration of this agent. This study used a lesion approach in rats to address the question of whether the dorsal most portion of the PBNl plays a key role in the acquisition of a conditioned avoidance to flavored stimuli induced by hypertonic sodium chloride (intra gastric), and whether this role is dependent on the flavor avoidance learning (FAL) paradigm used, concurrent (experiment 1) or delayed-sequential FAL (experiment 2). Results showed a clear disruptive effect of the PBNl electrolytic lesion on the acquisition of the concurrent FAL, but hardly any attenuation of the delayed-sequential FAL. This finding is discussed in the context of the hypothesis that two separate and apparently non-redundant routes exist for the processing of the visceral information.
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Sodium intake by hyperosmotic rats treated with a GABAA receptor agonist into the lateral parabrachial nucleus. Brain Res 2008; 1190:86-93. [DOI: 10.1016/j.brainres.2007.11.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Revised: 10/27/2007] [Accepted: 11/04/2007] [Indexed: 11/23/2022]
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25
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Serotonergic receptor blockade in the lateral parabrachial nucleus: Different effects on hypertonic and isotonic NaCl intake. Brain Res 2008; 1187:137-45. [DOI: 10.1016/j.brainres.2007.10.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Revised: 10/03/2007] [Accepted: 10/06/2007] [Indexed: 11/22/2022]
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26
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Godino A, De Luca LA, Antunes-Rodrigues J, Vivas L. Oxytocinergic and serotonergic systems involvement in sodium intake regulation: satiety or hypertonicity markers? Am J Physiol Regul Integr Comp Physiol 2007; 293:R1027-36. [PMID: 17567719 DOI: 10.1152/ajpregu.00078.2007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies demonstrated the inhibitory participation of serotonergic (5-HT) and oxytocinergic (OT) neurons on sodium appetite induced by peritoneal dialysis (PD) in rats. The activity of 5-HT neurons increases after PD-induced 2% NaCl intake and decreases after sodium depletion; however, the activity of the OT neurons appears only after PD-induced 2% NaCl intake. To discriminate whether the differential activations of the 5-HT and OT neurons in this model are a consequence of the sodium satiation process or are the result of stimulation caused by the entry to the body of a hypertonic sodium solution during sodium access, we analyzed the number of Fos-5-HT- and Fos-OT-immunoreactive neurons in the dorsal raphe nucleus and the paraventricular nucleus of the hypothalamus-supraoptic nucleus, respectively, after isotonic vs. hypertonic NaCl intake induced by PD. We also studied the OT plasma levels after PD-induced isotonic or hypertonic NaCl intake. Sodium intake induced by PD significantly increased the number of Fos-5-HT cells, independently of the concentration of NaCl consumed. In contrast, the number of Fos-OT neurons increased after hypertonic NaCl intake, in both depleted and nondepleted animals. The OT plasma levels significantly increased only in the PD-induced 2% NaCl intake group in relation to others, showing a synergic effect of both factors. In summary, 5-HT neurons were activated after body sodium status was reestablished, suggesting that this system is activated under conditions of satiety. In terms of the OT system, both OT neural activity and OT plasma levels were increased by the entry of hypertonic NaCl solution during sodium consumption, suggesting that this system is involved in the processing of hyperosmotic signals.
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Affiliation(s)
- Andrea Godino
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, Casilla de Correo 389, 5000-Córdoba, Argentina
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27
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Ho JM, Zierath DK, Savos AV, Femiano DJ, Bassett JE, McKinley MJ, Fitts DA. Differential effects of intravenous hyperosmotic solutes on drinking latency and c-Fos expression in the circumventricular organs and hypothalamus of the rat. Am J Physiol Regul Integr Comp Physiol 2006; 292:R1690-8. [PMID: 17194726 DOI: 10.1152/ajpregu.00547.2006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hyperosmotic intravenous infusions of NaCl are more potent for inducing drinking and vasopressin (AVP) secretion than equally osmotic solutions of glucose or urea. The fact that all three solutes increased cerebrospinal fluid osmolality and sodium concentration led the investigators to conclude that critical sodium receptors or osmoreceptors for stimulating drinking and AVP secretion were outside the blood-brain barrier (BBB) in the circumventricular organs (CVOs). We tested an obvious prediction of this hypothesis: that all three solutes should increase c-Fos-like immunoreactivity (Fos-ir) inside the BBB, but that only NaCl should increase Fos-ir in the CVOs. We gave intravenous infusions of 3.0 Osm/l NaCl, glucose, or urea to rats for 11 or 22 min at 0.14 ml/min and perfused the rats for assay of Fos-ir at 90 min. Controls received isotonic NaCl at the same volume. Drinking latency was measured, but water was then removed. Drinking consistently occurred with short latency during hyperosmotic NaCl infusions only. Fos-ir in the forebrain CVOs, the subfornical organ, and organum vasculosum laminae terminalis was consistently elevated only by hyperosmotic NaCl. However, all three hyperosmotic solutes potently stimulated Fos-ir in the supraoptic and paraventricular nuclei of the hypothalamus inside the BBB. Hyperosmotic NaCl greatly elevated Fos-ir in the area postrema, but even glucose and urea caused moderate elevations that may be related to volume expansion rather than osmolality. The data provide strong support for the conclusion that the osmoreceptors controlling drinking are located in the CVOs.
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Affiliation(s)
- Jacqueline M Ho
- Department of Psychology, University of Washington, Box 351525, Seattle, WA 98195-1525, USA
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28
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Andrade CAF, De Luca LA, Colombari DSA, Menani JV. Alpha2-adrenergic activation in the lateral parabrachial nucleus induces NaCl intake under conditions of systemic hyperosmolarity. Neuroscience 2006; 142:21-8. [PMID: 16890365 DOI: 10.1016/j.neuroscience.2006.04.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2006] [Revised: 04/10/2006] [Accepted: 04/13/2006] [Indexed: 10/24/2022]
Abstract
The inhibition of sodium intake by increased plasma osmolarity may depend on inhibitory mechanisms present in the lateral parabrachial nucleus. Activation of alpha(2)-adrenergic receptors in the lateral parabrachial nucleus is suggested to deactivate inhibitory mechanisms present in this area increasing fluid depletion-induced 0.3 M NaCl intake. Considering the possibility that lateral parabrachial nucleus inhibitory mechanisms are activated and restrain sodium intake in animals with increased plasma osmolarity, in the present study we investigated the effects on water and 0.3 M NaCl intake produced by the activation of alpha(2)-adrenergic receptors in the lateral parabrachial nucleus in rats with increased plasma osmolarity. Male Holtzman rats with stainless steel cannulas implanted bilaterally into the lateral parabrachial nucleus were used. One hour after intragastric 2 M NaCl load (2 ml), bilateral injections of moxonidine (alpha(2)-adrenergic/imidazoline receptor agonist, 0.5 nmol/0.2 microl, n=10) into the lateral parabrachial nucleus induced a strong ingestion of 0.3 M NaCl intake (19.1+/-5.5 ml/2 h vs. vehicle: 1.8+/-0.6 ml/2 h), without changing water intake (15.8+/-3.0 ml/2 h vs. vehicle: 9.3+/-2.0 ml/2 h). However, moxonidine into the lateral parabrachial nucleus in satiated rats not treated with 2 M NaCl produced no change on 0.3 M NaCl intake. The pre-treatment with RX 821002 (alpha(2)-adrenergic receptor antagonist, 20 nmol/0.2 microl) into the lateral parabrachial nucleus almost abolished the effects of moxonidine on 0.3 M NaCl intake (4.7+/-3.4 ml/2 h). The present results suggest that alpha(2)-adrenergic receptor activation in the lateral parabrachial nucleus blocks inhibitory mechanisms, thereby allowing ingestion of hypertonic NaCl under conditions of extracellular hyperosmolarity. We suggest that during cell dehydration, circuits subserving sodium appetite are activated, but at the same time strongly inhibited through the lateral parabrachial nucleus.
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Affiliation(s)
- C A F Andrade
- Department of Physiology and Pathology, School of Dentistry, Universidade Estadual Paulista, Rua Humaitá 1680, Araraquara, SP 14801-903, Brazil
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Freece JA, Van Bebber JE, Zierath DK, Fitts DA. Subfornical organ disconnection alters Fos expression in the lamina terminalis, supraoptic nucleus, and area postrema after intragastric hypertonic NaCl. Am J Physiol Regul Integr Comp Physiol 2005; 288:R947-55. [PMID: 15576664 DOI: 10.1152/ajpregu.00570.2004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The lamina terminalis was severed by a horizontal knife cut through the anterior commissure to determine the effects of a disconnection of the subfornical organ (SFO) on drinking and Fos-like immunoreactivity (Fos-ir) in the rat brain in response to an intragastric load of hypertonic saline (5 ml/kg of 1.5 M NaCl by gavage). After an initial load, knife-cut rats drank significantly less water than sham-cut rats, thus confirming a role for the SFO in osmotic drinking. After a second load at least 1 wk later, the rats were not allowed to drink after the gavage and were perfused for analysis of Fos-ir at 90 min. Compared with sham-cut rats, the knife-cut rats displayed significantly elevated Fos-ir in the main body of the SFO, in the dorsal cap of the organum vasculosum laminae terminalis, and in the ventral median preoptic nucleus after the hypertonic load. The knife cut significantly decreased Fos-ir in the supraoptic nucleus. Fos-ir was expressed mainly in the midcoronal and caudal parts of the area postrema of sham-cut rats, and this expression was greatly reduced in knife-cut rats. These findings strengthen the case for the presence of independently functioning osmoreceptors within the SFO and suggest that the structures of the lamina terminalis provide mutual inhibition during hypernatremia. They also demonstrate that the Fos-ir in the area postrema after intragastric osmotic loading is heavily dependent on the intact connectivity of the SFO.
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Affiliation(s)
- Julia A Freece
- Department Psychology, University of Washington, Box 351525, Seattle, WA 98195-1525, USA.
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30
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Osborn JW, Jacob F, Guzman P. A neural set point for the long-term control of arterial pressure: beyond the arterial baroreceptor reflex. Am J Physiol Regul Integr Comp Physiol 2005; 288:R846-55. [PMID: 15793038 DOI: 10.1152/ajpregu.00474.2004] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Arterial baroreceptor reflex control of renal sympathetic nerve activity (RSNA) has been proposed to play a role in long-term control of arterial pressure. The hypothesis that the “set point” of the acute RSNA baroreflex curve determines the long-term level of arterial pressure is presented and challenged. Contrary to the hypothesis, studies on the long-term effects of sinoaortic denervation (SAD) on arterial pressure and RSNA, as well as more recent studies of chronic baroreceptor “unloading” on arterial pressure, suggest that the basal levels of sympathetic nerve activity and arterial pressure are regulated independent of arterial baroreceptor input to the brainstem. Studies of the effect of SAD on the long-term salt sensitivity of arterial pressure are consistent with a short-term role, rather than a long-term role for the arterial baroreceptor reflex in regulation of arterial pressure during changes in dietary salt intake. Renal denervation studies suggest that renal nerves contribute to maintenance of the basal levels of arterial pressure. However, evidence that baroreflex control of the kidney plays a role in the maintenance of arterial pressure during changes in dietary salt intake is lacking. It is proposed that a “baroreflex-independent” sympathetic control system must exist for the long-term regulation of sympathetic nerve activity and arterial pressure. The concept of a central nervous system “set point” for long-term control of mean arterial pressure (CNS-MAP set point), and its involvement in the pathogenesis of hypertension, is discussed.
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Affiliation(s)
- John W Osborn
- Univ. of Minnesota, Dept. of Physiology, 6-125 Jackson Hall, 321 Church St., Minneapolis, MN 55455, USA.
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Richard S, Engblom D, Paues J, Mackerlova L, Blomqvist A. Activation of the parabrachio-amygdaloid pathway by immune challenge or spinal nociceptive input: a quantitative study in the rat using Fos immunohistochemistry and retrograde tract tracing. J Comp Neurol 2005; 481:210-9. [PMID: 15562506 DOI: 10.1002/cne.20384] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Peripheral nociceptive stimulation results in activation of neurons in the pontine parabrachial nucleus (PB) of rats. Electrophysiological studies have suggested that noxiously activated PB neurons project to the amygdala, constituting a potential pathway for emotional aspects of pain. In the present study we examined this hypothesis by combining retrograde tract tracing with Fos immunohistochemistry. Cholera toxin subunit B was injected into the amygdala of rats. After a minimum of 48 hours the rats were given a subcutaneous injection of 100 microl of 5% formalin into one hindpaw and killed 60-90 minutes later. A dense aggregation of retrogradely labeled neurons was seen in the external lateral PB. Fos-expressing neurons were present preferentially in the central, dorsal, and superior lateral subnuclei as well as in the lateral crescent area, as described previously. There was little overlap between the retrogradely labeled and Fos-expressing populations and double-labeled neurons were rare. In contrast, systemic immune challenge by intravenous injection of bacterial wall lipopolysaccharide resulted in a Fos expression that overlapped the retrograde labeling in the external lateral PB, and many double-labeled neurons were seen. While these data provide direct functional anatomical evidence that nociceptive information from the hindlimb is relayed to the amygdala via the parabrachial nucleus, the number of parabrachio-amygdaloid neurons involved is small. Considering the widespread activation of parabrachio-amygdaloid neurons by a variety of visceral and humoral stimuli, the parabrachio-amygdaloid pathway thus appears to be more involved in the mediation of information related to viscerally and humorally elicited activity than in transmission of spinal nociceptive inputs.
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Affiliation(s)
- Sabine Richard
- Station de Recherches Avicoles, Institut National de la Recherche Agronomique, 37 380 Nouzilly, France
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Callera JC, Oliveira LB, Barbosa SP, Colombari DSA, De Luca LA, Menani JV. GABAA receptor activation in the lateral parabrachial nucleus induces water and hypertonic NaCl intake. Neuroscience 2005; 134:725-35. [PMID: 16009500 DOI: 10.1016/j.neuroscience.2005.05.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2005] [Revised: 05/08/2005] [Accepted: 05/09/2005] [Indexed: 11/30/2022]
Abstract
Inhibitory serotonergic and cholecystokinergic mechanisms in the lateral parabrachial nucleus and central GABAergic mechanisms are involved in the regulation of water and NaCl intake. In the present study we investigated if the GABA(A) receptors in the lateral parabrachial nucleus are involved in the control of water, NaCl and food intake in rats. Male Holtzman rats with stainless steel cannulas implanted bilaterally into the lateral parabrachial nucleus were used. Bilateral injections of muscimol (0.2 nmol/0.2 microl) into the lateral parabrachial nucleus strongly increased 0.3 M NaCl (20.3+/-7.2 vs. saline: 2.6+/-0.9 ml/180 min) without changing water intake induced by the treatment with the diuretic furosemide combined with low dose of the angiotensin converting enzyme inhibitor captopril s.c. In euhydrated and satiated rats, bilateral lateral parabrachial nucleus injections of muscimol (0.2 and 0.5 nmol/0.2 microl) induced 0.3 M NaCl intake (12.1+/-6.5 and 32.5+/-7.3 ml/180 min, respectively, vs. saline: 0.4+/-0.2 ml/180 min) and water intake (5.2+/-2.0 and 7.6+/-2.8 ml/180 min, respectively, vs. saline: 0.8+/-0.4 ml/180 min), but no food intake (2+/-0.4 g/240 min vs. saline: 1+/-0.3 g/240 min). Bilateral lateral parabrachial nucleus injections of the GABA(A) antagonist bicuculline (1.6 nmol/0.2 microl) abolished the effects of muscimol (0.5 nmol/0.2 microl) on 0.3 M NaCl and water intake. Muscimol (0.5 nmol/0.2 microl) into the lateral parabrachial nucleus also induced a slight ingestion of water (4.2+/-1.6 ml/240 min vs. saline: 1.1+/-0.3 ml/240 min) when only water was available, a long lasting (for at least 2 h) increase on mean arterial pressure (14+/-4 mm Hg, vs. saline: -1+/-1 mm Hg) and only a tendency to increase urinary volume and Na+ and K+ renal excretion. Therefore the activation of GABA(A) receptors in the lateral parabrachial nucleus induces strong NaCl intake, a small ingestion of water and pressor responses, without changes on food intake.
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Affiliation(s)
- J C Callera
- Department of Basic Science, School of Dentistry, Paulista State University, UNESP, Araçatuba, SP, Brazil
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Menani JV, Barbosa SP, McKinley MJ, Wade JD, De Luca LA. Serotonergic mechanism of the lateral parabrachial nucleus and relaxin-induced sodium intake. Brain Res 2004; 1030:74-80. [PMID: 15567339 DOI: 10.1016/j.brainres.2004.09.048] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2004] [Indexed: 11/20/2022]
Abstract
It has been shown that central or peripheral injections of the peptide relaxin induces water intake, not sodium intake in rats. Important inhibitory mechanisms involving serotonin and other neurotransmitters in the control of water and NaCl intake have been demonstrated in the lateral parabrachial nucleus (LPBN). In the present study, we investigated the effects of bilateral injections of methysergide (serotonergic receptor antagonist) into the LPBN on intracerebroventricular (i.c.v.) relaxin-induced water and NaCl intake in rats. Additionally, the effect of the blockade of central angiotensin AT(1) receptors with i.c.v. losartan on relaxin-induced water and NaCl intake in rats treated with methysergide into the LPBN was also investigated. Male Holtzman rats with cannulas implanted into the lateral ventricle (LV) and bilaterally in the LPBN were used. Intracerebroventricular injections of relaxin (500 ng/1 microl) induced water intake (5.1+/-0.7 ml/120 min), but not significant 1.8% NaCl intake (0.5+/-0.4 ml/120 min). Bilateral injections of methysergide (4 microg/0.2 microl) into the LPBN strongly stimulated relaxin-induced 1.8% NaCl intake (34.5+/-10.9 ml/120 min) and slightly increased water intake (10.5+/-4.9 ml/120 min). The pretreatment with i.c.v. losartan (100 microg/1 microl) abolished the effects of i.c.v. relaxin combined with LPBN methysergide on 1.8% NaCl intake (0.5+/-0.4 ml/120 min). Losartan (100 microg/1 microl) also abolished relaxin-induced water intake in rats injected with methysergide into the LPBN (1.6+/-0.8 ml/120 min) or not (0.5+/-0.3 ml/120 min). Losartan (50 microg/1 microl) partially reduced the effects of relaxin. The results show that central relaxin interacting with central angiotensinergic mechanisms induces NaCl intake after the blockade of LPBN serotonergic mechanisms.
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Affiliation(s)
- J V Menani
- Department of Physiology and Pathology, School of Dentistry, Paulista State University, 14801-903 Araraquara, São Paulo, Brazil.
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Val-Laillet D, Meurisse M, Tillet Y, Nowak R. Differential c-Fos expression in the newborn lamb nucleus tractus solitarius and area postrema following ingestion of colostrum or saline. Brain Res 2004; 1028:203-12. [PMID: 15527745 DOI: 10.1016/j.brainres.2004.09.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2004] [Indexed: 11/23/2022]
Abstract
Visceral stimuli and the gut-brain axis play a crucial role in the control of ingestion even in the neonate. The aim of this study was to assess the neuronal activation in the nucleus tractus solitarius (NTS) and the area postrema (AP) following nutritional and non-nutritional stimulations. Lambs received a single gastric infusion of colostrum or saline at 5% birth weight or were sham infused. Infusion of either liquid led to c-Fos-like immunoreactivity (c-FLI) in the NTS and AP. Differences were observed along the sections of the NTS rostro-caudal axis according to the nature of the stimulation, suggesting a specificity of certain afferents and/or NTS areas for nutritional or non-nutritional signals. In the AP, the neuronal activation induced by colostrum was much higher than that induced by saline. A higher number of TH-immunoreactive cells were activated following colostrum infusion, suggesting a specific involvement of the catecholaminergic pathway in the treatment of meal-related stimuli. In spite of functional convergence, the two medullary structures observed responded differently according to the stimulation, indicating a complementary role in the integration of visceral signals.
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Affiliation(s)
- David Val-Laillet
- UMR 6175 CNRS-INRA-Université de Tours-Haras Nationaux, Equipe de Comportement, F-37380 Nouzilly, France
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Mazda T, Yamamoto H, Fujimura M, Fujimiya M. Gastric distension-induced release of 5-HT stimulates c-fos expression in specific brain nuclei via 5-HT3 receptors in conscious rats. Am J Physiol Gastrointest Liver Physiol 2004; 287:G228-35. [PMID: 14684379 DOI: 10.1152/ajpgi.00373.2003] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We examined c-fos expression in specific brain nuclei in response to gastric distension and investigated whether 5-HT released from enterochromaffin (EC) cells was involved in this response. The role of 5-HT3 receptors in this mechanism was also addressed. Release of 5-HT was examined in an ex vivo-perfused stomach model, whereas c-fos expression in brain nuclei induced by gastric distension was examined in a freely moving conscious rat model. Physiological levels of gastric distension stimulated the vascular release of 5-HT more than luminal release of 5-HT, and induced c-fos expression in the nucleus of the solitary tract (NTS), area postrema (AP), paraventricular nucleus (PVN), and supraoptic nucleus (SON). The c-fos expression in all these brain nuclei was blocked by truncal vagotomy as well as by perivagal capsaicin treatment, suggesting that vagal afferent pathways may mediate this response. Intravenous injection of 5-HT3 receptor antagonist granisetron blocked c-fos expression in all brain nuclei examined, although intracerebroventricular injection of granisetron had no effect, suggesting that 5-HT released from the stomach may activate 5-HT3 receptors located in the peripheral vagal afferent nerve terminals and then induce brain c-fos expression. c-fos Positive cells in the NTS were labeled with retrograde tracer fluorogold injected in the PVN, suggesting that neurons in the NTS activated by gastric distension project axons to the PVN. The present results suggest that gastric distension stimulates 5-HT release from the EC cells and the released 5-HT may activate 5-HT3 receptors located on the vagal afferent nerve terminals in the gastric wall leading to neuron activation in the NTS and AP and subsequent activation of neurons in the PVN and SON.
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Affiliation(s)
- Takayuki Mazda
- Dept. of Anatomy, Shiga University of Medical Science, Seta, Otsu, Shiga 520-2192
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36
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Abstract
Serotonin antagonism in the lateral parabrachial nucleus (LPBN) enhances sodium appetite induced by hypovolaemia and angiotensin-mineralocorticoid activation, but produces no sodium intake in euhydrated animals. In the present work, male adult rats (n=21) that received bilateral injections of the serotonergic antagonist methysergide (4 microg/0.2 microl) into the LPBN combined to intragastric load of 2 M NaCl (2 ml/rat), ingested hypertonic NaCl (ingestion of 4.3 +/- 1.6 ml/2 h of 0.3 M NaCl versus vehicle into LPBN: 0.2 +/- 0.2 ml/2 h, P<0.05). Methysergide- and vehicle-treated animals also ingested water (9.5 +/- 0.7 and 7.2+/-0.5 ml/2 h, respectively, P>0.05) as expected from the state of cell dehydration produced by the load. Ingestion of water (11.0 +/- 1.2 ml/2 h), and of 0.3 M NaCl (1.1 +/- 0.7 ml/2 h) were not altered by methysergide in NaCl loaded rats with misplaced LPBN injections (n=15).The ingestion of hypertonic NaCl by rats with serotonergic blockade in the LPBN suggests that the circuits subserving sodium appetite are activated, but at the same time strongly inhibited through the LPBN, during cell dehydration.
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Affiliation(s)
- L A De Luca
- Departamento Fisiologia e Patologia, Faculdade de Odontologia, Universidade Estadual Paulista, Rua Humaitá 1680, 14801-903 Araraquara, São Paulo, Brazil.
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Abstract
Projections to the parabrachial nucleus (PBN) from the nucleus of the solitary tract (NST) carry afferent signals from both the oral cavity and gastrointestinal tract. Although physiological studies suggest the convergence of oral and gastrointestinal sensory signals in the parabrachial nucleus, anatomical studies have emphasized the segregation of these pathways. To more precisely determine the anatomical relationship between gastric distension and oral afferent representation in PBN, small deposits of two anterograde tracers were made into the NST under physiological guidance in the same rat. Gastric terminations were dense and separate from taste projections in the rostral portion of the external lateral and dorsal lateral subnuclei. Gustatory projections were densest and separate from gastric terminations in the ventral lateral and central medial subnuclei of the caudal waist region, but were intermingled with gastric projections in these subnuclei and the external subnuclei at slightly more rostral levels. Patterns of segregation and overlap often appeared as 'patches' within or across subnuclear boundaries. In a second set of experiments, physiological evidence for overlap in PBN was evaluated from single unit extracellular responses evoked by gastric distension and orosensory (taste and orotactile) stimulation. Neurophysiological recordings verified that a small proportion of single cells within the waist and external subnuclei could be activated by both gastric and orotactile stimulation. The anatomical experiments further revealed intranuclear projections from the caudal NST injections that extended rostrally to sites at which responses to oral stimulation had been recorded. Although existing physiological data suggest such interactions are more limited than those in PBN, these anatomical data suggest that gastric/oral interactions may also exist in the NST.
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38
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Zafra MA, Simón MJ, Molina F, Puerto A. The role of the external lateral parabrachial subnucleus in flavor preferences induced by predigested food administered intragastrically. Brain Res 2002; 950:155-64. [PMID: 12231240 DOI: 10.1016/s0006-8993(02)03032-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A study was undertaken of the role of the external lateral parabrachial subnucleus (PBNLe) in flavor preferences induced by the intragastric administration of predigested/cephalic food. These preferences were developed using two different learning procedures, concurrent and sequential. In the concurrent procedure, two different-flavored stimuli were presented at the same time: one stimulus was paired with the simultaneous intragastric administration of partially digested food and the other with physiological saline. In the sequential learning procedure, the two stimuli were presented at alternate sessions. The results showed that PBNLe lesions blocked acquisition of concurrent learning but had no effect on the sequential procedure. In the latter case, both lesioned and control animals showed a strong preference for the gustatory stimulus paired with partially digested food. These results are interpreted in terms of a dual neurobiological system involved in the rewarding effects of visceral signals.
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Affiliation(s)
- M A Zafra
- Psychobiology Area, Department of Experimental Psychology and Physiology of Behavior, University of Granada, Campus de Cartuja, 18071, Granada, Spain.
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39
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Stricker EM, Callahan JB, Huang W, Sved AF. Early osmoregulatory stimulation of neurohypophyseal hormone secretion and thirst after gastric NaCl loads. Am J Physiol Regul Integr Comp Physiol 2002; 282:R1710-7. [PMID: 12010753 DOI: 10.1152/ajpregu.00548.2001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cerebral osmoreceptors mediate thirst and neurohypophyseal secretion stimulated by increases in the effective osmolality of plasma (P(osmol)). The present experiments determined whether an intragastric load of hypertonic saline (ig HS; 0.5 M NaCl, 4 ml) would potentiate these responses before induced increases in P(osmol) in the general circulation could be detected by cerebral osmoreceptors. Adult rats deprived of water overnight and then given intragastric HS consumed much more water in 15-30 min than rats given either pretreatment alone, even though systemic P(osmol) had not yet increased significantly because of the gastric load. In other rats pretreated with an intravenous infusion of 1 M NaCl (2 ml/h for 2 h), plasma levels of vasopressin and oxytocin were considerably elevated 15 and 25 min after intragastric HS treatment, whereas systemic P(osmol) was not increased further. These and other findings are consistent with previous reports that hepatic portal osmoreceptors (or Na(+) receptors) stimulate thirst and neurohypophyseal hormone secretion in euhydrated rats given gastric NaCl loads and indicate that these effects are potentiated when animals are dehydrated.
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Affiliation(s)
- Edward M Stricker
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
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40
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Cubero I, Lopez M, Navarro M, Puerto A. Lateral parabrachial lesions impair taste aversion learning induced by blood-borne visceral stimuli. Pharmacol Biochem Behav 2001; 69:157-63. [PMID: 11420081 DOI: 10.1016/s0091-3057(01)00494-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The lateral parabrachial area (LPB), main relay from the area postrema (AP), plays a role in processing visceral information and is thus of potential importance in taste aversion learning (TAL). This study used a lesion approach to address whether LPB functional relevance depends upon the features of toxins that serves as visceral stimuli in TAL. In addition, we explored whether LPB involvement in TAL is restricted to those toxic events detected by the AP or whether it has a more general role. Results showed that LPB-lesioned animals were disrupted in acquiring a TAL induced by blood-borne AP-dependent aversive stimuli (intraperitoneal methylscopolamine) and by AP-independent stimulus (intraperitoneal ethanol), but still, clearly developed strong aversions when intragastric hypertonic sodium chloride, a vagally processed aversive stimulus, served as the aversive stimulus. These findings suggest that the LPB plays a critical role in TAL induced by blood-borne toxins, such as methylscopolamine or ethanol, but is not necessary for vagally mediated stimulus, such as sodium chloride. The present results are discussed in the context of the hypothesis holding separable and independent neural systems underlying TAL.
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Affiliation(s)
- I Cubero
- Departamento de Psicología Experimental y Psicobiología, Universidad de Almería, 04120 Almería, Spain.
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41
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Doyle JA, Davis DP, Hoyt DB. The use of hypertonic saline in the treatment of traumatic brain injury. THE JOURNAL OF TRAUMA 2001; 50:367-83. [PMID: 11242309 DOI: 10.1097/00005373-200102000-00030] [Citation(s) in RCA: 156] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- J A Doyle
- Department of Emergency Medicine, University of California at San Diego, 200 West Arbor Drive, San Diego, CA 92103-8676, USA
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42
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Mediavilla C, Molina F, Puerto A. Electrolytic lesions of the pedunculopontine nucleus disrupt concurrent learned aversion induced by NaCl. Neurobiol Learn Mem 2000; 74:105-18. [PMID: 10933897 DOI: 10.1006/nlme.1999.3941] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Bilateral electrolytic lesions in the pedunculopontine nucleus (PPN) impair acquisition of short-term, or concurrent, Taste Aversion Learning (TAL) in rats. This type of TAL is characterized by the daily presentation of two different flavor stimuli at the same time, one associated with simultaneous intragastric administration of an aversive product (hypertonic NaCl) and the other with physiological saline. Sham-lesioned control animals learn this taste discrimination task, but both lesioned animals and control animals learn a long-term, or delayed, TAL task in which each gustatory stimulus is presented individually every other day and the intragastric products, LiCl (0.15 M) and physiological saline, are administered after a 15-min delay. These results are analyzed in the context of the cerebellar circuits involved in learning and in relation to the two TAL modalities described above.
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Affiliation(s)
- C Mediavilla
- Area de Psicobiología, Departamento de Psicología Experimental y Fisiología del Comportamiento, Universidad de Granada, Campus de Cartuja, Granada 18071, Spain.
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43
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Pritchard TC, Hamilton RB, Norgren R. Projections of the parabrachial nucleus in the old world monkey. Exp Neurol 2000; 165:101-17. [PMID: 10964489 DOI: 10.1006/exnr.2000.7450] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The efferent projections of the pontine parabrachial nucleus (PBN) were examined in the Old World monkey (Macaca fascicularis) using tritiated amino acid autoradiography and horseradish peroxidase histochemistry. Parabrachiofugal fibers ascended to the forebrain along three pathways: the central tegmental tract, the ventral ascending catecholaminergic pathway, and a pathway located on the midline between the medial longitudinal fasciculi. The PBN projected heavily to the central nucleus of the amygdala and the lateral division of the bed nucleus of the stria terminalis and moderately to the ventral tegmental area and the substantia nigra. Light terminal label also was present within the dorsomedial, ventromedial, lateral, supramammillary, and infundibular nuclei of the hypothalamus and the annular nucleus and the dorsal raphe nucleus within the brain stem. The overall pattern of terminal label was similar to that previously reported for nonprimate species, but several differences were notable. In monkey the projection to the ventrobasal thalamus did not coincide with the region that contains gustatory-responsive neurons. In rats, these parabrachiothalamic fibers convey gustatory activity but in the monkey these fibers may carry visceral afferent information. The projections from the PBN to the hypothalamus in the monkey were neither as widespread nor as intense as in the rat, and the monkey lacks a projection from the PBN to the frontal and insular cortices.
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Affiliation(s)
- T C Pritchard
- Department of Behavioral Science, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
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44
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Yamamoto T, Sawa K. Comparison of c-fos-like immunoreactivity in the brainstem following intraoral and intragastric infusions of chemical solutions in rats. Brain Res 2000; 866:144-51. [PMID: 10825490 DOI: 10.1016/s0006-8993(00)02242-3] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
To examine whether the activation of brainstem neurons during ingestion is due to orosensory afferents or post-ingestive factors, neuronal activation in response to intraoral and intragastric infusions of taste stimuli was compared in the area postrema (AP), nucleus tractus solitarius (NTS) and parabrachial nucleus (PBN) by the c-fos immunohistochemical method. An aliquot (7.5 ml) of 0.5 M sucrose, 5 mM sodium saccharin, 1 mM quinine hydrochloride and distilled water was delivered into the oral cavity or the stomach in each rat, which had been deprived of water and food overnight. Water induced little c-Fos-like immunoreactivity (c-FLI), but both intraoral and intragastric infusions of sucrose, but not non-caloric saccharin, induced strong c-FLI in the AP, caudal NTS and the external lateral subnucleus of the rostral PBN, suggesting that these areas receive general visceral inputs. Other areas in the NTS and PBN may receive gustatory inputs since more dominant c-FLI was detected by intraoral rather than intragastric infusions of the stimuli. Functional segregation of neurons reflecting qualitative and hedonic aspects of sweeteners (sucrose and saccharin) and bitter-tasting substance (quinine) was suggested in the PBN, but less evident in the NTS. These results indicate that c-fos induction in brainstem neurons during ingestion reflects gustatory inputs and postingestional factors depending on the kind of food ingested.
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Affiliation(s)
- T Yamamoto
- Department of Behavioral Physiology, Faculty of Human Sciences, Osaka University, 1-2 Yamadaoka, Suita, 565-0871, Osaka, Japan.
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45
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Yamamoto T, Sawa K. c-Fos-like immunoreactivity in the brainstem following gastric loads of various chemical solutions in rats. Brain Res 2000; 866:135-43. [PMID: 10825489 DOI: 10.1016/s0006-8993(00)02241-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The distribution of c-Fos-like immunoreactivity (c-FLI) in the lower brainstem especially in the area postrema (AP), nucleus of the tractus solitarius (NTS) and parabrachial nucleus (PBN) was examined following gastric loads of various chemical solutions in rats. An aliquot of 7.5 ml of each stimulus was intragastrically infused, and c-FLI was detected. The most remarkable c-FLI was induced by LiCl, lactose and ethanol which are known to be effective unconditioned stimuli in conditioned taste aversions. Polycose and disaccharides such as sucrose and maltose induced more c-FLI than monosaccharides such as glucose, fructose and galactose. Relatively low levels of c-FLI were observed for other sweeteners such as saccharin, glycine and alanine, and other basic taste stimuli such as NaCl, HCl, quinine and umami substances. Each stimulus induced a similar proportion of c-FLI among the subnuclei of the NTS, but not in the PBN, where chemicals effective in inducing conditioned taste aversions elicited stronger c-FLI in the external lateral subnucleus, and those in inducing conditioned taste preferences such as Polycose and glucose elicited stronger c-FLI in the dorsal lateral subnucleus. Vagotomy reduced c-FLI to about 50% for LiCl stimulation and to about 30% for sucrose stimulation, suggesting that LiCl has a larger proportion of extravagal inputs than sucrose.
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Affiliation(s)
- T Yamamoto
- Department of Behavioral Physiology, Faculty of Human Sciences, Osaka University, 1-2 Yamadaoka, Suita, 565-0871, Osaka, Japan.
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46
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Ruggiero DA, Underwood MD, Mann JJ, Anwar M, Arango V. The human nucleus of the solitary tract: visceral pathways revealed with an "in vitro" postmortem tracing method. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 2000; 79:181-90. [PMID: 10699650 DOI: 10.1016/s0165-1838(99)00097-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Visceral relay neurons in the nucleus of the solitary tract (NTS) regulate behavior and autonomic reflex functions. NTS projections have been extensively characterized in animal studies but not in humans. For the first time, NTS fiber trajectories in the human medulla oblongata were revealed with an "in vitro" postmortem tracing method. Local intramedullary pathways were labeled by direct pressure injections of free horseradish peroxidase centered on the medial subnucleus at a level adjacent to true obex. Labeled elements were resolved by peroxidase histochemistry as a dark brown intracellular reaction product. A prominent transtegmental system of axons emerged from the NTS injection sites and entered the intermediate reticular zone, a region corresponding to an autonomic reflex center in other mammals. A medial system of axons arched across the dorsomedial reticular formation toward the dorsal medullary raphe and projected ventrally toward the nucleus gigantocellularis. A small lateral fiber trajectory coursed towards the dorsomedial zone of spinal trigeminal nucleus caudalis. Presumptive terminals appeared as dustings of fine punctate processes within the NTS, dorsomotor nucleus and reticular formation. NTS projections in humans resemble those identified in other mammals including primates. Axonal tracing studies predict that visceral impulses in humans may transmit over evolutionarily conserved pathways involved in autonomic feedback control and stress adaptation.
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Affiliation(s)
- D A Ruggiero
- Columbia University College of Physicians and Surgeons, Department of Psychiatry, New York State Psychiatric Institute, New York, NY 10032, USA.
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47
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Rocha MJ, Beltz TG, Dornelles RC, Johnson AK, Franci CR. Anteroventral third ventricle (AV3V) lesions alter c-fos expression induced by salt loading. Brain Res 1999; 829:197-200. [PMID: 10350549 DOI: 10.1016/s0006-8993(99)01366-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Lesion of the anteroventral third-ventricle region (AV3VX) reduced saline consumption. Salt loading in AV3VX rats resulted in reduced but not completely abolished c-fos expression in the supraoptic and paraventricular nuclei. Intrinsic osmosensitivity of the magnocellular neurons, or input from other brain areas, such as the subfornical and median preoptic nuclei, may account for this residual c-fos expression. These regions showed c-fos expression following salt loading.
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Affiliation(s)
- M J Rocha
- Departamento de Fisiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, CEP 14049-900, Ribeirão Preto, SP, Brazil.
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48
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Yang G, Gray TS, Sigmund CD, Cassell MD. The angiotensinogen gene is expressed in both astrocytes and neurons in murine central nervous system. Brain Res 1999; 817:123-31. [PMID: 9889347 DOI: 10.1016/s0006-8993(98)01236-0] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Two transgenic mouse models were used to examine the cellular localization of angiotensinogen (AGT) in the brain. The first model was previously described in detail and consists of a human AGT genomic transgene containing all exons and introns of the gene and 1. 2 kb of the 5' flanking DNA. The second model contains a fusion between 1.2 kb of HAGT 5' flanking DNA and the beta-gal reporter gene which exhibits a similar pattern of tissue-specific expression to the HAGT transgene. Expression of both transgenes qualitatively mirrors the expression of endogenous AGT. Double staining of transgenic mouse brain sections with X-gal and GFAP revealed that a majority of beta-gal activity was localized to astrocytes in almost all brain areas. However, both beta-gal activity as identified by X-gal, and HAGT mRNA as detected by in situ hybridization, were also found in neurons in restricted areas of the brain, including the mesencephalic trigeminal nucleus (meV), subfornical organ (SFO) and the external lateral parabrachial nucleus (elPB). The expression of these transgenes provides the first convincing evidence for AGT gene expression in neurons in the brain. We further report by angiotensin II (Ang-II) immunostaining in rat brains after selective lesioning, that Ang-II is likely involved in a neuronal pathway from the PB to the amygdala (Ce). Finally, we performed double-labeling, first by retrograde labeling of HRP injected into the Ce, and then by X-gal on PB neurons in beta-gal transgenic mice, and identified doubly labeled neurons. Based on these results, we propose that AGT is generated in neurons in the elPB, transported to the Ce and converted into Ang-II locally to exert is biological functions.
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Affiliation(s)
- G Yang
- Department of Anatomy and Cell Biology, The University of Iowa College of Medicine, Iowa City, IA 52242, USA
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49
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Rowland NE. Brain mechanisms of mammalian fluid homeostasis: insights from use of immediate early gene mapping. Neurosci Biobehav Rev 1998; 23:49-63. [PMID: 9861612 DOI: 10.1016/s0149-7634(97)00068-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A comprehensive review of the literature through mid-1997 is presented on the application of immediate early gene mapping to problems related to brain mechanisms of fluid homeostasis and cardiovascular regulation in mammals. First, the basic mechanisms of fluid intake and the principles and pitfalls of immediate early gene mapping are briefly introduced. Then, data from several principal paradigms are reviewed. These include fluid deprivation and intracellular dehydration, both of which are associated with thirst and water intake. The contributions of peripheral sodium receptors, and of both hindbrain and forebrain integrative mechanisms are evaluated. Extracellular dehydration, and associated aspects of both thirst and sodium appetite are then reviewed. The contributions of both structures along the lamina terminalis and the hypothalamic magnocellular neurosecretory groups figure prominently in most of these paradigms. Effects of hypotension and hypertension are discussed, including data from the endogenous generation and the exogenous application of angiotensin II. Lastly, we summarize the contribution of the early gene mapping technique and consider briefly the prospects for new advances using this method.
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Affiliation(s)
- N E Rowland
- Department of Psychology, University of Florida, Gainesville 32611-2250, USA.
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50
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Osborn JW, Hornfeldt BJ. Arterial baroreceptor denervation impairs long-term regulation of arterial pressure during dietary salt loading. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 275:H1558-66. [PMID: 9815061 DOI: 10.1152/ajpheart.1998.275.5.h1558] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Experiments were performed to examine the contribution of arterial baroreceptors to long-term regulation of mean arterial pressure (MAP) during changes in dietary salt intake. Normotensive Sprague-Dawley rats were subjected to either sinoaortic denervation (SAD; n = 8) or Sham surgery (n = 6) and instrumented 1 wk later with radiotelemetry transmitters for continuous minute-to-minute monitoring of MAP and heart rate (HR) over the 8-wk protocol. Rats consumed three levels of dietary NaCl: 0.4% NaCl (week 1), 4.0% NaCl (weeks 2-4), and 8.0% NaCl (weeks 5-7). Rats returned to a 0.4% NaCl diet during the eighth week of the experiment. During week 1 (0.4% NaCl), there were no differences between Sham and SAD groups for 24-h averages of MAP or HR. However, by the third week of 4.0% NaCl, 24-h MAP was elevated significantly from baseline in SAD (10 +/- 2 mmHg) but not Sham (1 +/- 1 mmHg) rats. By the end of the third week of 8.0% NaCl diet, 24-h MAP was elevated 15 +/- 2 mmHg above control in SAD rats compared with a 4 +/- 1 mmHg increase in Sham rats (P < 0.05). Hourly analysis of the final 72 h of each level of dietary salt revealed a marked effect of dietary NaCl on MAP in SAD rats, particularly during the dark cycle. MAP increased approximately 20 and 30 mmHg in SAD rats over the 12-h dark cycle for 4.0 and 8.0% NaCl diets, respectively. In contrast, increased dietary NaCl had no effect on MAP during any phase of the light or dark period in Sham rats. These data support the hypothesis that arterial baroreceptors play a critical role in long-term regulation of MAP under conditions of altered dietary salt intake. Finally, hourly analysis of MAP revealed that the majority of the hypertensive response to increased NaCl occurs during the dark cycle in SAD rats. Hence, previous investigations may have underestimated the magnitude of the hypertensive response to increased dietary NaCl in animals with baroreceptor dysfunction.
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Affiliation(s)
- J W Osborn
- Departments of Physiology and Animal Science and the Graduate Program in Neuroscience, University of Minnesota, St. Paul, Minnesota 55108, USA
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