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De Luca LA, Laurin M, Menani JV. Control of fluid intake in dehydrated rats and evolution of sodium appetite. Physiol Behav 2024; 284:114642. [PMID: 39032667 DOI: 10.1016/j.physbeh.2024.114642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 07/04/2024] [Accepted: 07/17/2024] [Indexed: 07/23/2024]
Abstract
The objective of the present work is to examine from a new perspective the existence of causal factors not predicted by the classical theory that thirst and sodium appetite are two distinct motivations. For example, we ask why water deprivation induces sodium appetite, thirst is not "water appetite", and intracellular dehydration potentially causes sodium appetite. Contrary to the classical theory, we suggest that thirst first, and sodium appetite second, designate a temporal sequence underlying the same motivation. The single motivation becomes an "intervenient variable" a concept borrowed from the literature, fully explained in the text, between causes of dehydration (extracellular, intracellular, or both together), and respective behavioral responses subserved by hindbrain-dependent inhibition (e.g., lateral parabrachial nucleus) and forebrain facilitation (e.g., angiotensin II). A corollary is homology between rat sodium appetite and marine teleost thirst-like motivation that we name "protodipsia". The homology argument rests on similarities between behavior (salty water intake) and respective neuroanatomical as well as functional mechanisms. Tetrapod origin in a marine environment provides additional support for the homology. The single motivation hypothesis is also consistent with ingestive behaviors in nature given similarities (e.g., thirst producing brackish water intake) between the behavior of the laboratory rat and wild animals, rodents included. The hypotheses of single motivation and homology might explain why hyperosmotic rats, or eventually any other hyperosmotic tetrapod, shows paradoxical signs of sodium appetite. They might also explain how ingestive behaviors determined by dehydration and subserved by hindbrain inhibitory mechanisms contributed to tetrapod transition from sea to land.
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Affiliation(s)
- Laurival A De Luca
- Department of Physiology & Pathology, School of Dentistry, São Paulo State University (UNESP), 14801-903 Araraquara, São Paulo, Brazil.
| | - Michel Laurin
- CR2P, UMR 7207, CNRS/MNHN/SU, Muséum National d'Histoire Naturelle, Bâtiment de Géologie, CP 48, F-75231 Paris cedex 05, France
| | - José Vanderlei Menani
- Department of Physiology & Pathology, School of Dentistry, São Paulo State University (UNESP), 14801-903 Araraquara, São Paulo, Brazil
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Hu B, Qiao H, Sun B, Jia R, Fan Y, Wang N, Lu B, Yan JQ. AT1 receptor blockade in the central nucleus of the amygdala attenuates the effects of muscimol on sodium and water intake. Neuroscience 2015; 307:302-10. [PMID: 26344240 DOI: 10.1016/j.neuroscience.2015.08.069] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 08/27/2015] [Accepted: 08/30/2015] [Indexed: 10/23/2022]
Abstract
The blockade of the central nucleus of the amygdala (CeA) with the GABAA receptor agonist muscimol significantly reduces hypertonic NaCl and water intake by sodium-depleted rats. In the present study we investigated the effects of previous injection of losartan, an angiotensin II type-1 (AT1) receptor antagonist, into the CeA on 0.3M NaCl and water intake reduced by muscimol bilaterally injected into the same areas in rats submitted to water deprivation-partial rehydration (WD-PR) and in rats treated with the diuretic furosemide (FURO). Male Sprague-Dawley rats with stainless steel cannulas bilaterally implanted into the CeA were used. Bilateral injections of muscimol (0.2 nmol/0.5 μl, n=8 rats/group) into the CeA in WD-PR-treated rats reduced 0.3M NaCl intake and water intake, and pre-treatment of the CeA with losartan (50 μg/0.5 μl) reversed the inhibitory effect of muscimol. The negative effect of muscimol on sodium and water intake could also be blocked by pretreatment with losartan microinjected into the CeA in rats given FURO (n=8 rats/group). However, bilateral injections of losartan (50 μg/0.5 μl) alone into the CeA did not affect the NaCl or water intake. These results suggest that the deactivation of CeA facilitatory mechanisms by muscimol injection into the CeA is promoted by endogenous angiotensin II acting on AT1 receptors in the CeA, which prevents rats from ingesting large amounts of hypertonic NaCl and water.
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Affiliation(s)
- B Hu
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University, Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China; Department of Prosthodontics, Xi'an Jiaotong University, College of Stomatology, 98# Xiwu Road, Xi'an, Shaanxi 710004, PR China
| | - H Qiao
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University, Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China
| | - B Sun
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University, Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China
| | - R Jia
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University, Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China
| | - Y Fan
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University, Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China
| | - N Wang
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University, Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China
| | - B Lu
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University, Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China
| | - J Q Yan
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University, Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China.
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Yan JB, Sun HL, Wang Q, Chen K, Sun B, Song L, Yan W, Zhao XL, Zhao SR, Zhang Y, Qiao H, Hu B, Yan JQ. Natriorexigenic effect of DAMGO is decreased by blocking AT1 receptors in the central nucleus of the amygdala. Neuroscience 2013; 262:9-20. [PMID: 24389419 DOI: 10.1016/j.neuroscience.2013.12.046] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 12/20/2013] [Accepted: 12/21/2013] [Indexed: 11/17/2022]
Abstract
μ-Opioid receptor (μ-OR) activation with agonist [D-Ala², N-Me-Phe⁴, Gly⁵-ol]-enkephalin (DAMGO) in the central nucleus of the amygdala (CeA) induces sodium (0.3M NaCl) intake in rats. The purpose of this study was to examine the effects of pre-injections of losartan (AT1 angiotensin receptor antagonist) into the CeA on 0.3 M NaCl and water intake induced by DAMGO injected bilaterally in the same area in rats submitted to water deprivation-partial rehydration (WD-PR) and in rats treated with the diuretic furosemide (FURO) combined with a low dose of the angiotensin-converting enzyme inhibitor captopril (CAP) injected subcutaneously (FURO/CAP). Male Sprague-Dawley rats with stainless steel cannulas implanted bilaterally into the CeA were used. In WD-PR rats, bilateral injections of DAMGO (2 nmol in 0.5 μL) into the CeA induced 0.3 M NaCl and water intake, and pre-treatment with losartan (108 nmol in 0.5 μL) injected into the CeA reduced 0.3 M NaCl and water intake induced by DAMGO. In FURO/CAP rats, pre-treatment with losartan (108 nmol in 0.5 μL) injected into the CeA attenuated the increase in 0.3M NaCl and water intake induced by DAMGO (2 nmol in 0.5 μL) injected into the same site. The results suggest that the natriorexigenic effect of DAMGO injected into the CeA is facilitated by endogenous angiotensin II acting on AT1 receptors in the CeA, which drives rats to ingest large amounts of hypertonic NaCl.
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Affiliation(s)
- J-B Yan
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China; Department of Physiology, Medical College of Henan University of Science and Technology, 263# Kaiyuan Avenue, Luoyang, Henan 471023, PR China
| | - H-L Sun
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China; Department of Oral Biology, Xi'an Jiaotong University College of Stomatology, 98# Xiwu Road, Xi'an, Shaanxi 710004, PR China
| | - Q Wang
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China
| | - K Chen
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China
| | - B Sun
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China
| | - L Song
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China
| | - W Yan
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China
| | - X-L Zhao
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China
| | - S-R Zhao
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China
| | - Y Zhang
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China
| | - H Qiao
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China
| | - B Hu
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China
| | - J-Q Yan
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Health Science Center, 76# West Yanta Road, Xi'an, Shaanxi 710061, PR China; Department of Oral Biology, Xi'an Jiaotong University College of Stomatology, 98# Xiwu Road, Xi'an, Shaanxi 710004, PR China.
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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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