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Smardencas A, Denton DA, McKinley MJ. Hyperdipsia in sheep bearing lesions in the medial septal nucleus. Brain Res 2020; 1752:147223. [PMID: 33358728 DOI: 10.1016/j.brainres.2020.147223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 10/30/2020] [Accepted: 11/25/2020] [Indexed: 10/22/2022]
Abstract
Previous experiments in rodents showed that ablation of the septal brain region caused hyperdipsia. We investigated which part of the septal region needs ablation to produce hyperdipsia in sheep, and whether increased drinking was a primary hyperdipsia. Following ablation of the medial septal region (n = 5), but not parts of the lateral septal region (n = 4), daily water intake increased from ~2.5-5 L/day up to 10 L/day for up to 3 months post-lesion. In hyperdipsic sheep, plasma osmolality increased on the first day post-lesion and body weight fell, suggesting that initial hyperdipsia was secondary to fluid loss. However hyperosmolality was not sustained long-term and plasma hypo-osmolality persisted from 0.5 to 3 months post-lesion. Acute dipsogenic responses to intravenous hypertonic saline, intravenous or intracerebroventricular angiotensin II, water deprivation for 2 days, or feeding over 5 h were not potentiated by medial septal lesions, showing that the rapid pre-systemic inhibitory influences that cause satiation of thirst upon the act of drinking were intact. However, hyperdipsic sheep continued to ingest water when hyponatremic (plasma [Na] was 127-132 mmol/l) and plasma osmolality was 262-268 mosmol/kg due to retention of ingested fluid resulting from intravenous infusion of vasopressin administered to maintain a basal blood level of antidiuretic hormone. The results show that septal lesion-induced hyperdipsia is not due to disruption of acute pre-systemic influences associated with drinking water that initiates rapid satiation of thirst. Rather, inhibitory influences of hyponatremia, hypo-osmolality or hypervolemia on drinking appear to be disrupted by medial septal lesions.
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Affiliation(s)
- A Smardencas
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Vic 3010, Australia.
| | - D A Denton
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Vic 3010, Australia; Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Vic 3010, Australia; Baker IDI Heart and Diabetes Institute, Melbourne, Vic 3010, Australia.
| | - M J McKinley
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Vic 3010, Australia; Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Vic 3010, Australia; Department of Physiology, University of Melbourne, Melbourne, Vic 3010, Australia.
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Gavornik JP, Bear MF. Higher brain functions served by the lowly rodent primary visual cortex. ACTA ACUST UNITED AC 2014; 21:527-33. [PMID: 25225298 PMCID: PMC4175492 DOI: 10.1101/lm.034355.114] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
It has been more than 50 years since the first description of ocular dominance plasticity--the profound modification of primary visual cortex (V1) following temporary monocular deprivation. This discovery immediately attracted the intense interest of neurobiologists focused on the general question of how experience and deprivation modify the brain as a potential substrate for learning and memory. The pace of discovery has quickened considerably in recent years as mice have become the preferred species to study visual cortical plasticity, and new studies have overturned the dogma that primary sensory cortex is immutable after a developmental critical period. Recent work has shown that, in addition to ocular dominance plasticity, adult visual cortex exhibits several forms of response modification previously considered the exclusive province of higher cortical areas. These "higher brain functions" include neural reports of stimulus familiarity, reward-timing prediction, and spatiotemporal sequence learning. Primary visual cortex can no longer be viewed as a simple visual feature detector with static properties determined during early development. Rodent V1 is a rich and dynamic cortical area in which functions normally associated only with "higher" brain regions can be studied at the mechanistic level.
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Affiliation(s)
- Jeffrey P Gavornik
- Howard Hughes Medical Institute, The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Mark F Bear
- Howard Hughes Medical Institute, The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Learning reward timing in cortex through reward dependent expression of synaptic plasticity. Proc Natl Acad Sci U S A 2009; 106:6826-31. [PMID: 19346478 DOI: 10.1073/pnas.0901835106] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ability to represent time is an essential component of cognition but its neural basis is unknown. Although extensively studied both behaviorally and electrophysiologically, a general theoretical framework describing the elementary neural mechanisms used by the brain to learn temporal representations is lacking. It is commonly believed that the underlying cellular mechanisms reside in high order cortical regions but recent studies show sustained neural activity in primary sensory cortices that can represent the timing of expected reward. Here, we show that local cortical networks can learn temporal representations through a simple framework predicated on reward dependent expression of synaptic plasticity. We assert that temporal representations are stored in the lateral synaptic connections between neurons and demonstrate that reward-modulated plasticity is sufficient to learn these representations. We implement our model numerically to explain reward-time learning in the primary visual cortex (V1), demonstrate experimental support, and suggest additional experimentally verifiable predictions.
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Gottlieb HB, Ji LL, Jones H, Penny ML, Fleming T, Cunningham JT. Differential effects of water and saline intake on water deprivation-induced c-Fos staining in the rat. Am J Physiol Regul Integr Comp Physiol 2006; 290:R1251-61. [PMID: 16306162 DOI: 10.1152/ajpregu.00727.2005] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We studied c-Fos staining in adult male rats after 48 h of water deprivation and after 46 h of water deprivation with 2 h of access to water or physiological saline. Controls were allowed ad libitum access to water and physiological saline. For immunocytochemistry, anesthetized rats were perfused with a commercially available antibody for c-Fos. Dehydration significantly increased plasma vasopressin (AVP), osmolality, plasma renin activity (PRA), hematocrit, and sodium concentration and decreased urinary volume. Fos staining was significantly increased in the median preoptic nucleus, organum vasculosum of the lamina terminalis, supraoptic nucleus (SON), and magnocellular and parvocellular paraventricular nucleus (PVN), as well as the area postrema, nucleus of the solitary tract (NTS), and rostral ventrolateral medulla (RVL). Rehydration with water significantly decreased AVP levels and Fos staining in the SON, PVN, and RVL and significantly increased Fos expression in the perinuclear zone of the SON, NTS, and parabrachial nucleus. Rehydration with water was associated with decreased urinary sodium concentration and hypotonicity, and hematocrit and PRA were comparable to levels seen after dehydration. After rehydration with saline, plasma osmolality, hematocrit, and PRA were not different from control, but plasma AVP and urinary sodium concentration were increased. In the SON, Fos staining was significantly increased, with a great percentage of the Fos cells also stained for oxytocin compared with water deprivation. Changes in Fos staining were also observed in the NTS, RVL, parabrachial nucleus, and PVN. Rehydration with water or saline produces differential effects on plasma AVP, Fos staining, and sodium concentration.
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Affiliation(s)
- Helmut B Gottlieb
- Dept. of Pharmacology, UTHSCSA, 7703 Floyd Curl Dr., San Antonio, TX 78229, USA
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Pediconi D, Martarelli D, Fontanazza A, Pompei P. Effects of losartan and irbesartan administration on brain angiotensinogen mRNA levels. Eur J Pharmacol 2006; 528:79-87. [PMID: 16321381 DOI: 10.1016/j.ejphar.2005.10.062] [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] [Received: 10/06/2005] [Revised: 10/25/2005] [Accepted: 10/28/2005] [Indexed: 11/18/2022]
Abstract
Losartan, 2-n-butyl-4-chloro-5-hydroxymethyl-1-[(2'(1H-tetrazol-5-yl)-biphenil-4-yl)methyl]imidazole, and Irbesartan, 2-n-butyl-3-[(2'-(1H-tetrazol-5-yl)-biphenyl-4-yl)methyl]-1,3-diaza-spiro[4,4]non-1-en-4-one, are two angiotensin AT1 receptor antagonists largely used in human health care as antihypertensive agents. Their ability to cross the blood-brain barrier and to influence the central renin-angiotensin system are widely investigated, but how this brain system responds to the subchronic and chronic block of the angiotensin AT1 receptor is still unknown. Normotensive rats were intragastrically implanted for 7- and 30-day administration, with a dose of 3 and 30 mg/kg body weight. Treatments were shown to influence, in a dose-, time- and brain-area-dependent manner, angiotensinogen mRNA levels in scanned areas. This study showed a general up-regulation of angiotensinogen mRNA expression after 7 days and a widespread down-regulation or basal level of expression after a 30-day administration of two angiotensin AT1 receptor antagonists.
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Affiliation(s)
- Dario Pediconi
- Department of Experimental Medicine and Public Health, University of Camerino, Via Scalzino 3, 62032 Camerino (MC), Italy
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Penny ML, Bruno SB, Cornelius J, Higgs KAN, Cunningham JT. The effects of osmotic stimulation and water availability on c-Fos and FosB staining in the supraoptic and paraventricular nuclei of the hypothalamus. Exp Neurol 2005; 194:191-202. [PMID: 15899256 DOI: 10.1016/j.expneurol.2005.02.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2004] [Revised: 01/19/2005] [Accepted: 02/10/2005] [Indexed: 10/25/2022]
Abstract
We studied the effects of osmotic stimulation on the expression of FosB and c-Fos in the supraoptic nucleus (SON) and paraventricular nucleus (PVN). Adult male rats were divided into two groups that were injected with lidocaine (0.1-0.2 ml sc) followed by either 0.9% or 6% NaCl (1 ml/100 g bw sc). After the NaCl injections, the rats were anesthetized and perfused 2, 6, or 8 h after the injections. Their brains were prepared for immunocytochemistry and stained with FosB and c-Fos antibodies. The number of c-Fos-positive cells was significantly increased only at 2 h in the SON and PVN. In contrast, the number of FosB-positive cells was significantly increased at 6, and 8 h in both the SON and PVN. In a second experiment, the effect of water availability on FosB staining 8 h after injections of 6% NaCl was tested in 3 groups of rats: water ad libitum, rats that had no access to water, and rats that were given water 2 h prior to perfusion. FosB staining was significantly reduced in both the SON and the PVN of rats that had ad libitum water compared to the two water-restricted groups. In the third experiment, rats were injected with either 0.9% NaCl or 6% NaCl and were either given ad libitum access to water or water restricted for 6 h after the injections and perfused 24 h after the saline injections. FosB staining was not increased when water was available ad libitum. FosB staining was significantly increased at 24 h in the rats injected with 6% NaCl when water was restricted. Thus, FosB may continue to influence protein expression in the SON and PVN for at least 24 h following acute osmotic stimulation.
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Affiliation(s)
- Maurice L Penny
- Department of Pharmacology and the Center for Biomedical Neuroscience, University of Texas Health Sciences Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
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Sullivan EV, Deshmukh A, De Rosa E, Rosenbloom MJ, Pfefferbaum A. Striatal and forebrain nuclei volumes: contribution to motor function and working memory deficits in alcoholism. Biol Psychiatry 2005; 57:768-76. [PMID: 15820234 DOI: 10.1016/j.biopsych.2004.12.012] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2004] [Revised: 11/24/2004] [Accepted: 12/08/2004] [Indexed: 01/29/2023]
Abstract
BACKGROUND Striatal structures are involved in dopaminergic alcohol reward mechanisms and aspects of motor control. Basal forebrain structures hold cholinergic mechanisms influencing memory formation, vulnerable to chronic alcoholism; however, alcoholism's effect on volumes of these structures has seldom been considered with in vivo measurement. METHODS We measured bilateral volumes of caudate nucleus, putamen, nucleus accumbens, and medial septal/diagonal band (MS/DB) in 25 men with alcohol dependence and 51 age-matched control men. Six alcoholic subjects had been drinking recently, and 19 had been sober. RESULTS Volumes of caudate and putamen were smaller in the alcoholics than in the control subjects, regardless of length of sobriety. Recent drinkers showed greater deficits in nucleus accumbens than sober alcoholics. Putamen volume was positively correlated with grip strength; MS/DB volume was positively correlated with verbal working memory independently of the negative association between age-standardized MS/DB and age in alcoholics. CONCLUSIONS Caudate and putamen volume deficits occur and endure in chronic alcoholism. Nucleus accumbens might be especially sensitive to recent alcohol exposure. Striatal volumes should be considered in functional imaging studies of alcohol craving that target striatal brain regions. The age-alcohol interaction for MS/DB volumes is consistent with a cholinergic mechanism for the working memory impairment observed in the alcoholics.
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Affiliation(s)
- Edith V Sullivan
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA 94305-5723, USA.
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Ji LL, Fleming T, Penny ML, Toney GM, Cunningham JT. Effects of water deprivation and rehydration on c-Fos and FosB staining in the rat supraoptic nucleus and lamina terminalis region. Am J Physiol Regul Integr Comp Physiol 2005; 288:R311-21. [PMID: 15458969 DOI: 10.1152/ajpregu.00399.2004] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We studied cFos and FosB staining in the supraoptic nucleus (SON) the organum vasculosum of the lamina terminalis (OVLT) and the median preoptic nucleus (MnPO) in adult male rats after water deprivation (24 h, n = 11; 48 h, n = 12) and water deprivation with rehydration (22 h + water, n = 11; 46 h + water, n = 10). Control rats ( n = 15) had water available ad libitum. Separate sets of serial sections from each brain were processed for immunocytochemistry using primary antibodies against either c-Fos or FosB protein. Plasma osmolality, vasopressin, hematocrit, and plasma proteins were measured in separate groups ( n = 6–7). The number of c-Fos-positive cells in the SON was significantly increased after 24 and 48 h of water deprivation. In contrast, rehydrated groups were not different from control. Water deprivation significantly increased c-Fos staining in both the OVLT and the MnPO, but c-Fos staining was not altered by rehydration. FosB staining in the SON was significantly increased only by 48-h water deprivation, and this effect was significantly decreased by rehydration. In the MnPO and OVLT, FosB staining was significantly increased by water deprivation, and, like c-Fos staining, these increases were not affected by rehydration. Water deprivation significantly increased osmolality and hematocrit, as well as plasma protein and vasopressin concentrations. Plasma measurements from rehydrated rats were not different from control. We conclude that water deprivation and rehydration differentially affect c-Fos and FosB staining in a region-dependent manner.
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Affiliation(s)
- Lisa L Ji
- Department of Pharmacology, Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229, USA
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