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Blessing W, McAllen R, McKinley M. Control of the Cutaneous Circulation by the Central Nervous System. Compr Physiol 2016; 6:1161-97. [PMID: 27347889 DOI: 10.1002/cphy.c150034] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The central nervous system (CNS), via its control of sympathetic outflow, regulates blood flow to the acral cutaneous beds (containing arteriovenous anastomoses) as part of the homeostatic thermoregulatory process, as part of the febrile response, and as part of cognitive-emotional processes associated with purposeful interactions with the external environment, including those initiated by salient or threatening events (we go pale with fright). Inputs to the CNS for the thermoregulatory process include cutaneous sensory neurons, and neurons in the preoptic area sensitive to the temperature of the blood in the internal carotid artery. Inputs for cognitive-emotional control from the exteroceptive sense organs (touch, vision, sound, smell, etc.) are integrated in forebrain centers including the amygdala. Psychoactive drugs have major effects on the acral cutaneous circulation. Interoceptors, chemoreceptors more than baroreceptors, also influence cutaneous sympathetic outflow. A major advance has been the discovery of a lower brainstem control center in the rostral medullary raphé, regulating outflow to both brown adipose tissue (BAT) and to the acral cutaneous beds. Neurons in the medullary raphé, via their descending axonal projections, increase the discharge of spinal sympathetic preganglionic neurons controlling the cutaneous vasculature, utilizing glutamate, and serotonin as neurotransmitters. Present evidence suggests that both thermoregulatory and cognitive-emotional control of the cutaneous beds from preoptic, hypothalamic, and forebrain centers is channeled via the medullary raphé. Future studies will no doubt further unravel the details of neurotransmitter pathways connecting these rostral control centers with the medullary raphé, and those operative within the raphé itself. © 2016 American Physiological Society. Compr Physiol 6:1161-1197, 2016.
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Affiliation(s)
- William Blessing
- Human Physiology, Centre for Neuroscience, Flinders University, Adelaide, S.A., Australia
| | - Robin McAllen
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Vic., Australia
| | - Michael McKinley
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Vic., Australia
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Booth LC, Ramchandra R, Calzavacca P, May CN. Role of prostaglandins in determining the increased cardiac sympathetic nerve activity in ovine sepsis. Am J Physiol Regul Integr Comp Physiol 2014; 307:R75-81. [DOI: 10.1152/ajpregu.00450.2013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Effective treatment of sepsis remains a significant challenge in intensive care units. During sepsis, there is widespread activation of the sympathetic nervous system, which is thought to have both beneficial and detrimental effects. The sympathoexcitation is thought to be partly due to the developing hypotension, but may also be a response to the inflammatory mediators released. Thus, we investigated whether intracarotid infusion of prostaglandin E2 (PGE2) induced similar cardiovascular changes to those caused by intravenous infusion of Escherichia coli in sheep and whether inhibition of prostaglandin synthesis, with the nonselective cyclooxygenase inhibitor indomethacin, administered at 2 and 8 h after the onset of sepsis, reduced sympathetic nerve activity (SNA), and heart rate (HR). Studies were performed in conscious sheep instrumented to measure mean arterial pressure (MAP), HR, cardiac SNA (CSNA), and renal SNA (RSNA). Intracarotid infusion of PGE2 (50 ng·kg−1·min−1) increased temperature, CSNA, and HR, but not MAP or RSNA. Sepsis, induced by infusion of E. coli, increased CSNA, but caused an initial, transient inhibition of RSNA. At 2 h of sepsis, indomethacin (1.25 mg/kg bolus) increased MAP and caused reflex decreases in HR and CSNA. After 8 h of sepsis, indomethacin did not alter MAP, but reduced CSNA and HR, without altering baroreflex control. These findings indicate an important role for prostaglandins in mediating the increase in CSNA and HR during the development of hyperdynamic sepsis, whereas prostaglandins do not have a major role in determining the early changes in RSNA.
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Affiliation(s)
- Lindsea C. Booth
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Rohit Ramchandra
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Paolo Calzavacca
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Clive N. May
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
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May CN, Calzavacca P, Ishikawa K, Langenberg C, Wan L, Ramchandra R, Bellomo R. Novel targets for sepsis-induced kidney injury: the glomerular arterioles and the sympathetic nervous system. Exp Physiol 2012; 97:1168-77. [DOI: 10.1113/expphysiol.2011.061804] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Ramchandra R, Wan L, Hood SG, Frithiof R, Bellomo R, May CN. Septic shock induces distinct changes in sympathetic nerve activity to the heart and kidney in conscious sheep. Am J Physiol Regul Integr Comp Physiol 2009; 297:R1247-53. [DOI: 10.1152/ajpregu.00437.2009] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sepsis and septic shock are the chief cause of death in intensive care units, with mortality rates between 30 and 70%. In a large animal model of septic shock, we have demonstrated hypotension, increased cardiac output, and tachycardia, together with renal vasodilatation and renal failure. The changes in cardiac sympathetic nerve activity (CSNA) that may contribute to the tachycardia have not been investigated, and the changes in renal SNA (RSNA) that may mediate the changes in renal blood flow and function are unclear. We therefore recorded CSNA and RSNA during septic shock in conscious sheep. Septic shock was induced by administration of Escherichia coli, which caused a delayed hypotension and an immediate, biphasic increase in heart rate (HR) associated with similar changes in CSNA. After E. coli, RSNA decreased for over 3 h, followed by a sustained increase (180%), whereas renal blood flow progressively increased and remained elevated. There was an initial diuresis, followed by oliguria and decreased creatinine clearance. There were differential changes in the range of the arterial baroreflex curves; it was depressed for HR, increased for CSNA, and unchanged for RSNA. Our findings, recording CSNA for the first time in septic shock, suggest that the increase in SNA to the heart is not driven solely by unloading of baroreceptors and that the increase has an important role to increase HR and cardiac output. There was little correlation between the changes in RSNA and renal blood flow, suggesting that the renal vasodilatation was mediated mainly by other mechanisms.
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Affiliation(s)
- Rohit Ramchandra
- Howard Florey Institute, University of Melbourne, Parkville, Australia
| | - Li Wan
- Howard Florey Institute, University of Melbourne, Parkville, Australia
| | - Sally G. Hood
- Howard Florey Institute, University of Melbourne, Parkville, Australia
| | - Robert Frithiof
- Howard Florey Institute, University of Melbourne, Parkville, Australia
| | - Rinaldo Bellomo
- Howard Florey Institute, University of Melbourne, Parkville, Australia
| | - Clive N. May
- Howard Florey Institute, University of Melbourne, Parkville, Australia
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Malpas SC, Ramchandra R, Guild SJ, McBryde F, Barrett CJ. Renal sympathetic nerve activity in the development of hypertension. Curr Hypertens Rep 2007; 8:242-8. [PMID: 17147923 DOI: 10.1007/s11906-006-0057-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
With increasing evidence that the sympathetic nervous system plays a critical role in the development of hypertension, focus is turning to how these signals translate to a chronic increase in arterial pressure. The kidney's role in the control of salt and water homeostasis makes it an obvious target for such investigations. However, to date many studies have been restricted to experiments that last only a few hours, or at most, a few days, whereas others may use indirect methods of assessing sympathetic activity rather than direct recordings. We review current approaches used to determine the effects of renal sympathetic nerve activity (SNA) on arterial pressure and suggest possible avenues of future investigation. We propose that although afferent inputs, such those as from chemoreceptors and baroreceptors, are important for the short-term control of blood pressure via regulation of SNA to multiple organs, it is highly likely that alternative signals are important for setting the long-term level of renal SNA. Emerging evidence indicates that circulating angiotensin II is a hormone that may act on the central nervous system to regulate renal SNA, renal function, and, therefore, blood pressure. Future studies on the genesis of hypertension should focus more on determining the mediators of long-term levels of renal SNA.
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Affiliation(s)
- Simon C Malpas
- Circulatory Control Laboratory, Department of Physiology, University of Auckland Medical School, Private Bag 92019, Auckland, New Zealand?
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Guild SJ, Barrett CJ, Malpas SC. LONG-TERM RECORDING OF SYMPATHETIC NERVE ACTIVITY: THE NEW FRONTIER IN UNDERSTANDING THE DEVELOPMENT OF HYPERTENSION? Clin Exp Pharmacol Physiol 2005; 32:433-9. [PMID: 15854154 DOI: 10.1111/j.1440-1681.2005.04207.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
1. With increasing evidence that the sympathetic nervous system plays a critical role in the development of hypertension, focus is turning to how these signals translate to a chronic increase in arterial pressure. 2. The kidney's role in the control of salt and water homeostasis makes it an obvious target for such investigations. However, to date, many studies have been restricted to experiments lasting only a few hours or, at most, a few days, whereas others may use indirect methods of assessing sympathetic activity rather than direct recordings. 3. We review current approaches used to determine the effects of renal sympathetic nerve activity (SNA) on arterial pressure and suggest possible avenues of future investigation. We propose that although afferent inputs, such as from chemoreceptors and baroreceptors, are important for the short-term control of blood pressure via regulation of SNA to multiple organs, it is highly likely that alternative signals are important for setting the long-term level of renal SNA. 4. Emerging evidence indicates circulating angiotensin II is hormone that may act on the central nervous system to regulate renal SNA, renal function and, thus, blood pressure. 5. We propose that an integral part of future studies seeking an understanding of the genesis of hypertension should include chronic direct recordings of renal SNA.
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Affiliation(s)
- Sarah-Jane Guild
- Circulatory Control Laboratory, Department of Physiology, University of Auckland, Auckland, New Zealand.
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Nomoto S, Shibata M, Iriki M, Riedel W. Role of afferent pathways of heat and cold in body temperature regulation. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2004; 49:67-85. [PMID: 15549421 DOI: 10.1007/s00484-004-0220-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2003] [Revised: 05/22/2004] [Accepted: 05/22/2004] [Indexed: 05/24/2023]
Abstract
The detection of surface and internal temperatures is achieved by axons terminating at lamina I of the spinal dorsal horn, otherwise approached only by nociceptive afferents. Recent advances in thermal physiology research have disclosed that temperature-sensitive ion channels belonging to the "transient receptor potential" family exist in the peripheral sensory neurons and in the brain. Thermosensory, nociceptive and polymodal afferents project to different thalamic nuclei, and specific pathways to the insular cortex evoke the conscious experience of thermal sensation. The posterior insular region represents discriminative thermal sensation, while the largest correlation with subjective ratings of temperature is located in the orbitofrontal and anterior insular cortex. The insular cortex forms an integrative part of the limbic system and is closely tied with the hypothalamus, the amygdala, the anterior cingulate cortex and the orbitofrontal cortex and emerges as the main coordinator of behavioral, autonomic and endocrine responses to both non-noxious and noxious thermal stimuli. The firing rate of warm and cold receptors is not altered by pyrogens. A strong correlation between the onset of fever and production of superoxide by macrophages following the injection of pyrogens implicates reactive oxygen species as elicitors of fever, a hypothesis strengthened by the observation that oxygen radical scavengers or thiol reductants act as antipyretics. Oxidative stress appears to be sensed by the brain and a likely structure for its detection may be the redox-sensitive site of the N-methyl-D-aspartate (NMDA) receptor for glutamate, in that oxidation of this site causes fever while its reduction lowers body temperature, effects which are abrogated by specific NMDA receptor blockers.
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Affiliation(s)
- Shigeki Nomoto
- Tokyo Metropolitan Institute of Gerontology, 173-0015 Tokyo, Japan.
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Horiuchi J, McAllen RM, Allen AM, Killinger S, Fontes MAP, Dampney RAL. Descending vasomotor pathways from the dorsomedial hypothalamic nucleus: role of medullary raphe and RVLM. Am J Physiol Regul Integr Comp Physiol 2004; 287:R824-32. [PMID: 15205184 DOI: 10.1152/ajpregu.00221.2004] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The dorsomedial hypothalamic nucleus (DMH) is believed to play a key role in mediating vasomotor and cardiac responses evoked by an acute stress. Inhibition of neurons in the rostral ventrolateral medulla (RVLM) greatly reduces the increase in renal sympathetic nerve activity (RSNA) evoked by activation of the DMH, indicating that RVLM neurons mediate, at least in part, the vasomotor component of the DMH-evoked response. In this study, the first aim was to determine whether neurons in the medullary raphe pallidus (RP) region also contribute to the DMH-evoked vasomotor response, because it has been shown that the DMH-evoked tachycardia is mediated by the RP region. The second aim was to directly assess the effect of DMH activation on the firing rate of RVLM sympathetic premotor neurons. In urethane-anesthetized rats, injection of the GABA(A) receptor agonist muscimol (but not vehicle solution) in the RP region caused a modest ( approximately 25%) but significant reduction in the increase in RSNA evoked by DMH disinhibition (by microinjection of bicuculline). In other experiments, disinhibition of the DMH resulted in a powerful excitation (increase in firing rate of approximately 400%) of 5 out of 6 spinally projecting barosensitive neurons in the RVLM. The results indicate that neurons in the RP region make a modest contribution to the renal sympathoexcitatory response evoked from the DMH and also that sympathetic premotor neurons in the RVLM receive strong excitatory inputs from DMH neurons, consistent with the view that the RVLM plays a key role in mediating sympathetic vasomotor responses arising from the DMH.
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Affiliation(s)
- J Horiuchi
- Dept. of Physiology, F13, The Univ. of Sydney, NSW 2006, Australia
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Burke SL, Head GA. Method for in vivo calibration of renal sympathetic nerve activity in rabbits. J Neurosci Methods 2003; 127:63-74. [PMID: 12865149 DOI: 10.1016/s0165-0270(03)00121-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A major difficulty of recording from peripheral sympathetic nerves is that microvolt values reflect characteristics of the recording conditions and limit comparisons between different experimental groups. In this study we assessed methods of calibrating renal sympathetic nerve activity (RSNA) in conscious rabbits. Calibration values were obtained from maximum RSNA responses to nasopharyngeal stimulation, airjet stress or unloading baroreceptors. Curves relating RSNA to blood pressure were produced by raising and lowering blood pressure with vasoactive drugs. To assess whether normalization would eliminate differences between RSNA curves which were most likely due to recording conditions, rabbits were first divided into two groups with high or low basal microvolt levels of RSNA, then again into two groups with high or low heart rate. In both cases, curves were similar if values were normalized by nasopharyngeal stimulation or by the upper plateau value. In hypertensive rabbits, where the baroreflex is suppressed, only the nasopharyngeal method showed this attenuated pattern. This method also eliminated the 50% decay in basal RSNA measured over 5 weeks. We conclude that expressing RSNA in terms of the maximum response to nasopharyngeal stimulation provides a calibration method suitable for comparing nerve activity over the long term as well as showing valid differences in baroreflex curves between different experimental groups.
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Affiliation(s)
- Sandra L Burke
- Neuropharmacology Laboratory, Baker Heart Research Institute, Commercial Road Prahran, PO Box 6492, St Kilda Road Central, Melbourne, Vic. 8008, Australia
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DiBona GF, Jones SY. Effect of sodium intake on sympathetic and hemodynamic response to thermal receptor stimulation. Hypertension 2003; 41:261-5. [PMID: 12574092 DOI: 10.1161/01.hyp.0000052829.50997.fe] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Low dietary sodium intake increases central nervous system angiotensin activity, which increases basal renal sympathetic nerve activity and shifts its arterial baroreflex control to a higher level of arterial pressure. This results in a higher level of renal sympathetic nerve activity for a given level of arterial pressure during low dietary sodium intake than during either normal or high dietary sodium intake, in which there is less central angiotensin activity. Peripheral thermal receptor stimulation overrides arterial baroreflex control and produces a pressor response, tachycardia, increased renal sympathetic nerve activity, and renal vasoconstriction. To test the hypothesis that increased central angiotensin activity would enhance the responses to peripheral thermal receptor stimulation, anesthetized normal rats in balance on low, normal, and high dietary sodium intake were subjected to acute peripheral thermal receptor stimulation. Low sodium rats had greater increases in renal sympathetic nerve activity, greater decreases in RBF, and greater increases in renal vascular resistance than high sodium rats. Responses of normal sodium rats were between those of low and high sodium rats. Arterial pressure and heart rate responses were not different among dietary groups. Spontaneously hypertensive rats, known to have increased central nervous system angiotensin activity, also had greater renal sympathoexcitatory and vasoconstrictor responses than normotensive Wistar-Kyoto rats. These results support the view that increased central nervous system angiotensin activity alters arterial baroreflex control of renal sympathetic nerve activity such that the renal sympathoexcitatory and vasoconstrictor responses to peripheral thermoreceptor stimulation are enhanced.
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Affiliation(s)
- Gerald F DiBona
- Department of Internal Medicine, University of Iowa College of Medicine, and Veterans Administration Medical Center, Iowa City 52242, USA.
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Chu C, Jin Q, Kunitake T, Kato K, Nabekura T, Nakazato M, Kangawa K, Kannan H. Cardiovascular actions of central neuromedin U in conscious rats. REGULATORY PEPTIDES 2002; 105:29-34. [PMID: 11853869 DOI: 10.1016/s0167-0115(01)00381-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Neuromedin U (NMU) is a brain-gut peptide, which peripherally stimulates smooth muscle, increases of blood pressure, alters ion transport in the gut, controls local blood flow, and regulates adrenocortical function. Although intracerebroventricular (i.c.v.) administration of NMU is known to decrease food intake and body weight, little is known about its effect on other physiological functions. We examined the effects of i.c.v. administration of NMU on mean arterial pressure (MAP), heart rate (HR), and plasma norepinephrine in conscious rats. Neuromedin U (0.05 and 0.5 nmol) provoked an increase in MAP (93.8 +/- 0.5 to 123.5 +/- 1.7 and 94.7 +/- 0.8 to 132.7 +/- 3.0 mm Hg, respectively) and HR (334.9 +/- 6.0 to 494.1 +/- 6.9 and 346.3 +/- 3.3 to 475.1 +/- 8.9 beats/min, respectively). In contrast, plasma norepinephrine increased only with a high dose of neuromedin U. Intravenously administered NMU (0.5 nmol) elicited a small and short lasting increase in MAP, compared to that by i.c.v. NMU. These results indicate that central neuromedin U regulates sympathetic nervous system activity and affects cardiovascular function.
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Affiliation(s)
- Chunping Chu
- Department of Physiology, Miyazaki Medical College, 5200 Kihara, Kiyotake-cho, Miyazaki-gun, Miyazaki 889-1692, Japan
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Abstract
Patients with fever have a predisposition to experience dehydration, which may alter their thermoregulatory responses to elevated body temperature. In view of the recent discovery of the antipyretic activity of arginine vasopressin (AVP), it is possible that dehydration has a beneficial role during fever. Dehydration may enhance endogenous antipyresis by stimulating AVP release, making aggressive fluid replacement, which may inhibit AVP release, undesirable during fever. This study addressed the effects of manipulation of hydration status on temperature and cardiovascular responses in endotoxin-injected rabbits. Eight unanesthetized chronically instrumented rabbits were exposed to lipopolysaccharide (LPS) while in euhydrated state, after furosemide (5 mg/kg) and 24 hours of water deprivation (dehydrated), after infusion of saline (30 mL/kg) while in euhydrated state (hyperhydrated), and after saline (mL/per overnight body weight loss in grams) while in dehydrated state (rehydrated). Dehydrated rabbits display higher fevers that are biphasic in nature and are accompanied by increased vasoconstriction and duration of mean arterial pressure increases, indicating that activation of antipyretic mechanisms in dehydrated rabbits was not sufficient to reduce body core temperature. In addition, fluid supplementation in euhydrated rabbits did not alter the febrile response; however, a marked decrease in heart rate was noted. Furthermore, fluid supplementation in dehydrated rabbits significantly attenuates the rectal temperature and heart rate response to LPS injection, indicating the possibility that activation of antipyretic mechanisms of AVP in rehydrated rabbits was sufficient to reduce body core temperature. The results suggest that fluid supplementation has a beneficial role in keeping body temperature lower .
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Affiliation(s)
- C A Richmond
- Mt. Sinai Medical Center, Miami Heart Institute, Miami Beach, FL, USA.
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DiBona GF. Neural control of the kidney: functionally specific renal sympathetic nerve fibers. Am J Physiol Regul Integr Comp Physiol 2000; 279:R1517-24. [PMID: 11049831 DOI: 10.1152/ajpregu.2000.279.5.r1517] [Citation(s) in RCA: 138] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The sympathetic nervous system provides differentiated regulation of the functions of various organs. This differentiated regulation occurs via mechanisms that operate at multiple sites within the classic reflex arc: peripherally at the level of afferent input stimuli to various reflex pathways, centrally at the level of interconnections between various central neuron pools, and peripherally at the level of efferent fibers targeted to various effectors within the organ. In the kidney, increased renal sympathetic nerve activity regulates the functions of the intrarenal effectors: the tubules, the blood vessels, and the juxtaglomerular granular cells. This enables a physiologically appropriate coordination between the circulatory, filtration, reabsorptive, excretory, and renin secretory contributions to overall renal function. Anatomically, each of these effectors has a dual pattern of innervation consisting of a specific and selective innervation by unmyelinated slowly conducting C-type renal sympathetic nerve fibers in addition to an innervation that is shared among all the effectors. This arrangement permits the maximum flexibility in the coordination of physiologically appropriate responses of the tubules, the blood vessels, and the juxtaglomerular granular cells to a variety of homeostatic requirements.
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Affiliation(s)
- G F DiBona
- Departments of Internal Medicine and Physiology, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA.
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Dibona GF. Differentiation of vasoactive renal sympathetic nerve fibres. ACTA PHYSIOLOGICA SCANDINAVICA 2000; 168:195-200. [PMID: 10691800 DOI: 10.1046/j.1365-201x.2000.00643.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Activation of renal sympathetic nerves produces marked changes in renal haemodynamics, tubular ion and water transport and renin secretion. This review examines information indicating that these effects are mediated by functionally specific groups of renal sympathetic nerve fibres separately innervating the renal vessels, tubules and juxtaglomerular granular cells.
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Affiliation(s)
- G F Dibona
- Departments of Internal Medicine & Physiology, University of Iowa College of Medicine and Veterans Administration Medical Center, Iowa City, Iowa 52242, USA
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Kozyreva TV, Tkachenko EY, Kozaruk VP, Latysheva TV, Gilinsky MA. Effects of slow and rapid cooling on catecholamine concentration in arterial plasma and the skin. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:R1668-72. [PMID: 10362746 DOI: 10.1152/ajpregu.1999.276.6.r1668] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Norepinephrine (NE) and epinephrine (Epi) concentrations in arterial plasma and in skin tissue were measured chromatographically before and after external cooling. Urethan-anesthetized rats were cooled either slowly (0.004-0.006 degrees C/s) or rapidly (0.03- 0.05 degrees C/s). Blood samples were drawn three times from each animal: 1) before cooling and at a rectal temperature decreased 2) by 0.5 degrees C and 3) by 3-4 degrees C. Skin samples were taken from controls and from rapidly or slowly cooled rats at a rectal temperature lowered by 0.5 degrees C. The resting mean values were 36.7 +/- 0.3 degrees C for rectal temperature, 0.62 +/- 0.079 and 1. 09 +/- 0.203 ng/ml for plasma NE and Epi, and 85.6 +/- 4.1 and 137.6 +/- 34.3 ng/g for skin NE and Epi. A decrease in rectal temperature by 0.5 degrees C at rapid cooling produced a 2.6-fold increase of NE and a 2.8-fold increase of Epi in plasma. Concomitantly, there was a significant decrease in skin NE concentration by 28% and Epi by 86%. At a rectal temperature decreased by 0.5 degrees C after slow cooling, plasma catecholamines did not change; at unaltered skin NE concentration, there was a reduction in skin Epi concentration (60%). When rectal temperature was lowered by 3-4 degrees C, the increase in plasma NE was virtually the same at both cooling rates and only plasma Epi increased more after deep rapid cooling than slow cooling. Thus the sympathoadrenal system may be differently activated depending on cooling rate. Rapid cooling, when the dynamic activity of the skin cold receptors is involved in the cold response, may provide conditions for an earlier activation of the sympathoadrenal system. This may evidence the functional significance of the dynamic activity of the skin cold receptors in the formation of the cold defense responses.
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Affiliation(s)
- T V Kozyreva
- Institute of Physiology, Novosibirsk 630117, Russia.
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DiBona GF, Sawin LL. Renal hemodynamic effects of activation of specific renal sympathetic nerve fiber groups. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:R539-49. [PMID: 9950935 DOI: 10.1152/ajpregu.1999.276.2.r539] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To examine the effect of activation of a unique population of renal sympathetic nerve fibers on renal blood flow (RBF) dynamics, anesthetized rats were instrumented with a renal sympathetic nerve activity (RSNA) recording electrode and an electromagnetic flow probe on the ipsilateral renal artery. Peripheral thermal receptor stimulation (external heat) was used to activate a unique population of renal sympathetic nerve fibers and to increase total RSNA. Total RSNA was reflexly increased to the same degree with somatic receptor stimulation (tail compression). Arterial pressure and heart rate were increased by both stimuli. Total RSNA was increased to the same degree by both stimuli but external heat produced a greater renal vasoconstrictor response than tail compression. Whereas both stimuli increased spectral density power of RSNA at both cardiac and respiratory frequencies, modulation of RBF variability by fluctuations of RSNA was small at these frequencies, with values for the normalized transfer gain being approximately 0.1 at >0.5 Hz. During tail compression coherent oscillations of RSNA and RBF were found at 0.3-0.4 Hz with normalized transfer gain of 0.33 +/- 0.02. During external heat coherent oscillations of RSNA and RBF were found at both 0.2 and 0.3-0.4 Hz with normalized transfer gains of 0. 63 +/- 0.05 at 0.2 Hz and 0.53 +/- 0.04 to 0.36 +/- 0.02 at 0.3-0.4 Hz. Renal denervation eliminated the oscillations in RBF at both 0.2 and 0.3-0.4 Hz. These findings indicate that despite similar increases in total RSNA, external heat results in a greater renal vasoconstrictor response than tail compression due to the activation of a unique population of renal sympathetic nerve fibers with different frequency-response characteristics of the renal vasculature.
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Affiliation(s)
- G F DiBona
- Departments of Internal Medicine and Physiology, University of Iowa College of Medicine; and Veterans Administration Medical Center, Iowa City, Iowa 52242, USA
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DiBona GF, Jones SY. Reflex effects on components of synchronized renal sympathetic nerve activity. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 275:F441-6. [PMID: 9729518 DOI: 10.1152/ajprenal.1998.275.3.f441] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of peripheral thermal receptor stimulation (tail in hot water, n = 8, anesthetized) and cardiac baroreceptor stimulation (volume loading, n = 8, conscious) on components of synchronized renal sympathetic nerve activity (RSNA) were examined in rats. The peak height and peak frequency of synchronized RSNA were determined. The renal sympathoexcitatory response to peripheral thermal receptor stimulation was associated with an increase in the peak height. The renal sympathoinhibitory response to cardiac baroreceptor stimulation was associated with a decrease in the peak height. Although heart rate was significantly increased with peripheral thermal receptor stimulation and significantly decreased with cardiac baroreceptor stimulation, peak frequency was unchanged. As peak height reflects the number of active fibers, reflex increases and decreases in synchronized RSNA are mediated by parallel increases and decreases in the number of active renal nerve fibers rather than changes in the centrally based rhythm or peak frequency. The increase in the number of active renal nerve fibers produced by peripheral thermal receptor stimulation reflects the engagement of a unique group of silent renal sympathetic nerve fibers with a characteristic response pattern to stimulation of arterial baroreceptors, peripheral and central chemoreceptors, and peripheral thermal receptors.
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Affiliation(s)
- G F DiBona
- Department of Internal Medicine, University of Iowa College of Medicine, and Veterans Affairs Medical Center, Iowa City, Iowa 52242, USA
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19
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Iriki M, Saigusa T. Regional differentiation of sympathetic efferents during fever. PROGRESS IN BRAIN RESEARCH 1998; 115:477-97. [PMID: 9632948 DOI: 10.1016/s0079-6123(08)62048-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- M Iriki
- Yamanashi Institute of Environmental Sciences, Japan
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20
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Sakurada S, Hales JR. A role for gastrointestinal endotoxins in enhancement of heat tolerance by physical fitness. J Appl Physiol (1985) 1998; 84:207-14. [PMID: 9451637 DOI: 10.1152/jappl.1998.84.1.207] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
To further elucidate mechanisms underlying the higher heat tolerance of physically fit compared with sedentary people, we have investigated the possibility that endotoxins (of gastrointestinal origin) act, as in the normal development of fever, to raise body temperature and therefore reduce heat tolerance. In an initial series of experiments, five physically fit and four sedentary sheep were exposed twice at rest to an environment of 42/35 degrees C (dry/wet bulb temperature). When animals were given normal saline i.v., rectal temperature (Tre) rose at a significantly higher rate in sedentary than in fit animals; this confirms that heat tolerance is improved by physical fitness. Treatment with i.v. indomethacin did not affect the rate of rise of Tre in fit animals. In sedentary animals, however, Tre was lowered to approximate that of fit animals. Because indomethacin blocks prostaglandin pathways involved in endotoxin-induced fever, the indomethacin-induced improvement of heat tolerance of sedentary but not fit animals supports the contention that endotoxins play a role in determining that difference in heat tolerance. In a second series of experiments, quantitative cardiovascular measurements were made by using radioactive microspheres. Under normothermic conditions, blood flows in the brain, ileum, and diaphragm were higher in fit than in sedentary animals. During hyperthermia up to Tre of 42 degrees C (in a 42/39 degrees C environment), fit compared with sedentary animals exhibited 1) a greater increase in cardiac output, 2) an increase in blood flow through arteriovenous anastomoses to higher and better maintained levels, 3) less reduction in blood flow to the ileum, and 4) greater increase in blood flows to the myocardium, turbinates, nasal mucosa, and respiratory muscles. Endotoxins are likely to come from the gut lumen, because reduction of gut blood flow forms part of the normal response to heat stress. We suggest that improvement of heat tolerance by physical fitness is caused by a greater cardiovascular capacity that permits not only greater perfusion of heat-loss tissues but the maintenance of a better gastrointestinal tract blood supply, thereby better maintaining the normal barrier to movement of endotoxins from gut lumen to plasma. Sedentary people, with their lower cardiovascular capacity, redistribute more blood flow away from the gut during environmentally induced hyperthermia, thus allowing endotoxin-induced fever to aggravate hyperthermia.
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Affiliation(s)
- S Sakurada
- School of Physiology and Pharmacology, University of New South Wales, Sydney, Australia.
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21
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Keil R, Riedel W, Simon E. Hormonal secretion patterns but not autonomic effector responses elicited by hypothalamic heating and cooling are altered in febrile rabbits. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1996; 57:193-201. [PMID: 8964949 DOI: 10.1016/0165-1838(95)00072-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The effects of hypothalamic heating and cooling on thermoregulatory effector activities, lipid and carbohydrate metabolism, insulin, glucagon, thyroxine, arginine vasopressin (AVP) and cortisol were investigated in conscious rabbits and compared with those obtained in the febrile state. The study shows that under control conditions hypothalamic heating lowers, and cooling raises core temperature. Core temperature always rose to similar degrees in response to bacterial lipopolysaccharide (LPS) during an observation time of 150 min, but it started to rise from lower and higher levels, respectively, during hypothalamic heating and cooling. The effects of hypothalamic thermal stimulation on specific thermoregulatory effector activities support the conclusion that, within 60 min after LPS, the hypothalamic warm signal input is reduced relative to the cold signal input. The increase of thyroxine levels following LPS suggests that the elevation of the thermoregulatory setpoint was caused by an increased input of hypothalamic TRH neurons, known to induce the full autonomic pattern of cold defense also in response to non-thermal stimuli. With the exception of an increase of glucagon during hypothalamic cooling at control conditions, hypothalamic thermal stimulation alone did not alter lipid and carbohydrate metabolism, insulin, thyroid hormone, AVP and cortisol secretion. A spontaneous heat loss effector response separated the first from the second fever phase 60 min after LPS. Subsequently AVP and cortisol plasma levels rose in febrile animals, irrespective of hypothalamic heating and cooling, presumably as a consequence of pyrogenic activation of corticotropin releasing factor (CRF) producing neurons and their reciprocal interaction with TRH neurons on the one hand, and by a reciprocal interaction of the latter with AVP neurons on the other.
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Affiliation(s)
- R Keil
- Max-Planck-Institut für Physiologische, W.G. Kerckhoff-Institut, Bad Nauheim, Germany
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22
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Matsukawa T, Kashimoto S, Kumazawa T, Miyaji T, Hashimoto M, Iriki M. Effects of halothane and enflurane on the peripheral vasoconstriction and shivering induced by internal body cooling in rabbits. J Anesth 1994; 8:311-5. [DOI: 10.1007/bf02514657] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/1993] [Accepted: 12/16/1993] [Indexed: 10/24/2022]
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Ichijo T, Katafuchi T, Hori T. Central interleukin-1 beta enhances splenic sympathetic nerve activity in rats. Brain Res Bull 1994; 34:547-53. [PMID: 7922597 DOI: 10.1016/0361-9230(94)90139-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The central administration of immune cytokines such as interleukin-1 (IL-1) and interferon-alpha (IFN-alpha) results in the suppression of peripheral cellular immunity, which depends, at least partly, on the sympathetic nervous activity. An intrathird cerebroventricular (I3V) infusion of recombinant human IL-1 beta (rhIL-1 beta) (1-5 ng/rat) elicited a dose-dependent increase in the electrical activity of the splenic sympathetic nerve in urethane and alpha-chloralose anesthetized rats. The effect of rhIL-1 beta (1 ng/rat) was completely blocked by pretreatment with an IL-1 receptor antagonist (1 microgram/rat, I3V 10 min before rhIL-1 beta), sodium salicylate (1 microgram/rat), or alpha-melanocyte stimulating hormone (alpha-MSH) (400 ng/rat). Furthermore, an antagonist of corticotropin-releasing factor (CRF), alpha-helical CRF9-41 (2 micrograms/rat), completely abolished the rhIL-1 beta-induced increase in the splenic nerve activity, although an I3V infusion of CRF (1 microgram/rat) excited it. These results suggest that IL-1 beta in the brain activates splenic sympathetic activity by its receptor-mediated and prostaglandin-dependent action that is sensitive to alpha-MSH, depending on CRF system. Our findings, together with the previous results, suggest that the splenic sympathetic nerve represents one of the communication channels from the brain to the immune system.
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Affiliation(s)
- T Ichijo
- Department of Physiology, Faculty of Medicine, Kyushu University 60, Fukuoka, Japan
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24
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Huang XC. Effects of hypothalamic microinjection of PGE2 on body temperature and sympathetic nervous activities in the rabbit. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 1993; 37:222-228. [PMID: 8112881 DOI: 10.1007/bf01387528] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The febrile response and sympathetic nervous response to hypothalamic microinjections of prostaglandin E2 (PGE2) were investigated in anesthetized rabbits. Microinjection of PGE2 (500-1000 ng) caused an increase in rectal temperature of more than 0.3 degrees C in 13 of 50 loci in the preoptic and anterior hypothalamic area (PO/AH). At 8 of these 13 loci, PGE2 elicited response patterns in the sympathetic nervous system, such as an increase in cutaneous sympathetic nervous activity and decrease in renal sympathetic nervous activity. This pattern of sympathetic nervous responses was induced with a simultaneous increase in rectal temperature of more than 0.5 degrees C. The 8 loci were distributed in the preoptic area, especially in the vicinity of the supraoptic nucleus. Electrolytic lesions of this region were made bilaterally, and intracerebroventricular injection of PGE2 (8 micrograms/kg) was found to inhibit fever and sympathetic activity. The results demonstrate that the action of PGE2 is responsible for the response patterns of sympathetic twigs during fever. The preoptic area, especially in the vicinity of the supraoptic nucleus, is most sensitive to PGE2 for the patternized response of sympathetic neurons and fever.
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Affiliation(s)
- X C Huang
- Department of Physiology, Medical University of Yamanashi, Japan
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25
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Abstract
The effects of TRH and its metabolically stable analog NS-3 [(3R,6R)-6-methyl-5-oxo-3-thiomorpholinylcarbonyl-L-histidyl-L-pro linamide tetrahydrate] on thermoregulation and circulatory control have been investigated. Both NS-3 (1-100 ng/kg ICV) and TRH (0.1-10 micrograms/kg ICV) increased rectal temperature and metabolic rate with a transient cutaneous vasoconstriction in conscious rabbits. They also increased arterial blood pressure, heart rate, respiratory rate, and renal sympathetic nerve activity (RSNA) in urethane-anesthetized rabbits. Ten ng/kg of NS-3 and 10 micrograms/kg of TRH had comparable hyperthermic, pressor, and tachycardic activities, while the relative potency of NS-3 to increase RSNA was greater and that to increase metabolic rate was smaller than the other effects. In conclusion, NS-3 was more potent than TRH in all of the effects measured, but there was a dissociation in the relative potency of NS-3 in the different autonomic effects.
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Affiliation(s)
- X C Huang
- Department of Physiology, Yamanashi Medical College, Japan
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26
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Niijima A, Hori T, Aou S, Oomura Y. The effects of interleukin-1 beta on the activity of adrenal, splenic and renal sympathetic nerves in the rat. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1991; 36:183-92. [PMID: 1787257 DOI: 10.1016/0165-1838(91)90042-2] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The effects of intravenous (i.v.) administration of recombinant human interleukin-1 beta (rhIL-1 beta) on the activity of adrenal, splenic and renal sympathetic nerves were observed in urethane-anesthetized rats. An i.v. injection of IL-1 beta in doses of 10 pg-20 ng per animal (300-400 g, b.w.) resulted in a dose-dependent increase in the activity of the adrenal and splenic nerves, which lasted for more than 2-6 h. On the other hand, the activity of renal nerves showed a transient increase which was followed by a long-lasting suppression after injection of rhIL-1 beta (100 pg, i.v.). An i.v. injection of cyclooxygenase inhibitors (6 mg ibuprofen or 20 mg sodium salicylate) suppressed almost completely the rhIL-1 beta (100 pg)-induced activity in adrenal and splenic nerves. Although rhIL-1 beta (100 pg, i.v.) produced a fall in arterial blood pressure, baroreceptor denervation did not affect the excitatory responses of the adrenal and splenic nerves to rhIL-1 beta. The results suggest the regional differentiation of activity in the visceral sympathetic nerves in response to rhIL-1 beta. The rhIL-1 beta-induced activation of splenic sympathetic nerves implicates their involvement in the modulation of immunity by brain.
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Affiliation(s)
- A Niijima
- Department of Physiology, Niigata University School of Medicine, Japan
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Nishimura C, Kanemaru K, Otagiri T. Characteristic changes between core and peripheral surface temperature related with postanesthetic shivering following surgical operations. J Anesth 1990; 4:350-7. [PMID: 15235968 DOI: 10.1007/s0054000040350] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/1989] [Accepted: 03/19/1990] [Indexed: 11/28/2022]
Abstract
The relationship between changes in the core and the surface temperature and postanesthetic shivering was studied in 100 patients who underwent general anesthesia. Patients were classified into four groups by the patterns of change in the core and peripheral surface temperature. Type II and type IV groups of patients showed a decrease in surface temperature during the major operation such as gastrectomy and radical mastectomy. Type I and type III groups of patients showed no lowered peripheral surface temperature and with low temperature difference between core and surface temperature during the operation. The patients in type II and IV groups showed increased difference between core and surface temperature. The postanesthetic shivering occurred at significantly higher rate compared to the other two groups. As possible reasons of the shivering, operation of long duration and insufficient circulating blood volume were considered. Shivering reduces the temperature difference in the thermoregulatory homeostasis. However, in patients in type I and III, the rate of shivering was low. Evaluation of the difference between core and peripheral surface temperature may be important to manage body temperature at a steady level during the operation. The monitoring of body temperature difference between core and peripheral surface during the operation may be useful for predicting to occurrence of postanesthetic shivering.
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Affiliation(s)
- C Nishimura
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Matsumoto, Japan
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28
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29
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Saigusa T. Participation of interleukin-1 and tumor necrosis factor in the responses of the sympathetic nervous system during lipopolysaccharide-induced fever. Pflugers Arch 1990; 416:225-9. [PMID: 2381761 DOI: 10.1007/bf00392057] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The regional sympathetic responses during fevers induced by an exogenous pyrogen, lipopolysaccharide, and by two endogenous pyrogens, interleukin-1 beta (IL-1 beta) and tumor necrosis factor alpha (TNF-alpha), were compared in urethane-anesthetized rabbits. Rectal temperature (Tre), ear skin temperature (Tear) as an index for cutaneous sympathetic activity, renal sympathetic nerve activity (RSNA) representing visceral efferents, arterial blood pressure, and heart rate were recorded during fever caused by intravenous injections of each of the three pyrogens. Lipopolysaccharide (1 micrograms/kg i.v.) caused prolonged fever of more than 3 h duration with a tendency towards a biphasic course of temperature, whereas fevers induced by IL-1 beta (1 microgram/kg i.v.) and TNF-alpha (10 micrograms/kg i.v.) were monophasic with a maximum between the 45th and 60th min. Each of the three pyrogens typically induced a decrease in Tear, indicative of cutaneous sympathetic activation, and simultaneous inhibition of RSNA during the first phase of rising Tre. RSNA tended to increase again approximately to its control level when the maximum Tre had been attained after the injection of each pyrogen. When the second rising phase of lipopolysaccharide fever started, Tear decreased once more, but RSNA remained at its control level. Taken together with the enhancement of IL-1 and TNF production during lipopolysaccharide-induced fever, the present results suggest the participation of these endogenous pyrogens in the responses of the sympathetic nervous system during the early phase of the lipopolysaccharide induced fever.
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Affiliation(s)
- T Saigusa
- Department of Physiology, Yamanashi Medical College, Japan
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30
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Affiliation(s)
- W Riedel
- Max-Planck-Institut für physiologische und klinische Forschung, W.G. Kerckhoff-Institut, Bad Nauheim, Germany
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31
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Saigusa T, Iriki M. Regional differentiation of sympathetic nerve activity during fever caused by intracerebroventricular injection of PGE2. Pflugers Arch 1988; 411:121-5. [PMID: 3357750 DOI: 10.1007/bf00582303] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In urethane-anesthetized rabbits prostaglandin E2 (PGE2) injected into a lateral cerebral ventricle (icv) produced hyperthermia. During the phase of rising rectal temperature, renal sympathetic activity monitored by multi-unit recording was reduced while the drop of ear skin temperature indicated cutaneous sympathetic activation. These reciprocal changes in activity corresponded to those typical for cold stress as well as for the phase of rising body temperature in fever induced by endotoxic lipopolysaccharides (LPS). However, a slight early stimulation of the heart rate after icv PGE2, contrasted to the initial reductions seen with LPS fever and in the cold. After sino-aortic denervation renal sympathetic inhibition in response to icv PGE2 was reduced but not abolished. After cervical vagotomy the antagonism between cutaneous and visceral sympathetic activity and the increase in heart rate became more prominent. During the phase of subsiding hyperthermia after icv PGE2, renal sympathetic activity returned to its control level, but, unlike LPS fever, did not exceed it. The results of this study indicate that the reciprocal changes in cutaneous and renal sympathetic activity, but not of sympathetic outflow to the heart, are identical during the phase of rising temperature in PGE2 and LPS fever. During the phase of subsiding hyperthermia, renal sympathetic activities change to different extents in PGE2 and LPS fever.
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Affiliation(s)
- T Saigusa
- Department of Physiology, Yamanashi Medical College, Japan
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32
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Wenzel C, Werner J. Physical versus pharmacological counter-measures. Studies on febrile rabbits. EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY 1988; 57:81-8. [PMID: 3342798 DOI: 10.1007/bf00691243] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
128 experiments were carried out on febrile rabbits at air temperatures of 8, 18, 24 and 30 degrees C in order to analyze the thermoregulatory effects and mechanisms of physical and/or pharmacological counter-measures. Fever was achieved by injection of 0.1 micrograms Salmonella typhi endotoxin (LPS)/kg into an ear vein. As the pharmacological counter-measure, injections of acetylsalicylic acid (ASA) into an ear vein were chosen. For the physical counter-measure, cooling thermodes (5 degrees C) were constructed for the abdominal skin, for the ear and for the rectum. ASA injections had no effect on the first fever maximum, even if applied 20 to 60 min before the LPS injection, but eliminated the second fever maximum. Of course, the additional hyperthermia observed at 30 degrees C ambient temperature could not be eliminated by the injections. On the other hand, cooling procedures can obviously not affect the pyrogen-induced temperature increase, but reduce the hyperthermic effect of a higher ambient temperature. Rectal cooling was more effective than ear or abdominal skin cooling. Abdominal cooling evoked an increase in metabolic heat production. Application of combined physical and pharmacological counter-measures achieved the strongest and quickest reduction of the second maximum, whereas the first maximum was not affected, as in all other experiments. The study emphasizes the necessity of taking into account the time course of the effector mechanisms in order to discriminate between hyperthermic and febrile components of temperature increase. In the initial phase cooling measures would evoke unwanted regulatory responses of the effectors, whereas during the second febrile maximum they would achieve a quicker reduction of core temperatures.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- C Wenzel
- Institut für Physiologie, Ruhr-Universität, Bochum, Federal Republic of Germany
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33
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Clark WG. Changes in body temperature after administration of antipyretics, LSD, delta 9-THC and related agents: II. Neurosci Biobehav Rev 1987; 11:35-96. [PMID: 3033566 DOI: 10.1016/s0149-7634(87)80003-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Antipyretics, in particular acetaminophen, aspirin and ibuprofen, constitute the single most important class of drugs used therapeutically for an effect on body temperature. Hallucinogens exert prominent actions on the central nervous system, and it is not surprising that, like so many other centrally-acting agents, they too often affect temperature. This compilation primarily covers the considerable amount of data published from 1981 through 1985 on the interactions of these drugs and thermoregulation, but data from many earlier papers not included in a previous compilation are also tabulated. The effects of agents not classically considered as antipyretics on temperatures of febrile subjects are also covered. The information listed includes the species used, the route of administration and dose of drug, the environmental temperature at which experiments were performed, the number of tests, the direction and magnitude of change in body temperature and remarks on special conditions, such as age or brain lesions. Also indicated is the influence of other drugs, such as antagonists, on the response to the primary agent.
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Dorward PK, Burke SL, Jänig W, Cassell J. Reflex responses to baroreceptor, chemoreceptor and nociceptor inputs in single renal sympathetic neurones in the rabbit and the effects of anaesthesia on them. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1987; 18:39-54. [PMID: 3819315 DOI: 10.1016/0165-1838(87)90133-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Reflex responses of renal postganglionic neurones to stimulation of arterial baroreceptors, arterial and central chemoreceptors and cutaneous nociceptors, and the rhythmicity of their resting activity were studied in paralyzed, artificially ventilated rabbits, anaesthetized with either alfathesin or chloralose-urethane. A 'vasoconstrictor' response pattern was seen in all units. Perivascular balloon-induced falls in blood pressure increased firing while pressure rises silenced 90% of units and reduced firing in the rest. Resting activity was linked to pressure changes within the cardiac cycle and to the artificial respiratory cycle. The largest excitation occurred during hypoxia and injections of CO2 saturated solutions into the carotid artery while hypercapnia and stimulation of cutaneous nociceptors only slightly increased firing. Parameters characterizing rhythmicities and reflex responses were unimodally distributed with no apparent subgrouping of units on quantitative grounds. Unit response patterns were similar to those recorded in the whole renal nerve. With one exception, no silent units were found which responded to the afferent inputs studied. Nor was there a small-spike fibre group which was excited by angiotensin. However, reflex responses were significantly influenced by the anaesthetic regime selected for use. Under alfathesin, baroreceptor and chemoreceptor reflexes were double those found with chloralose-urethane. Under chloralose-urethane, hypoxia increased both rhythmicities, while under alfathesin, cardiac rhythmicity was decreased and respiratory rhythmicity was variably affected. We concluded that renal sympathetic neurones are a functionally uniform population which behave like vasoconstrictors.
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35
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Gagało IT, Hać EE. The acid-base balance during the time course of endotoxin fever and sodium salicylate antipyresis in the rabbit. PHARMACOLOGICAL RESEARCH COMMUNICATIONS 1986; 18:17-30. [PMID: 3081916 DOI: 10.1016/0031-6989(86)90156-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Blood acid-base balance in sodium salicylate antipyresis was investigated in adult rabbits at ambient temperature of 21.5 +/- 0.5 degrees C. The experimental fever elicited by iv injection of lipopolysaccharide Escherichia coli 1 microgram/kg/ was accompanied by a slight metabolic acidosis. A decrease in pH by 0.09 and HCO3- by 4.8 mEq/1 was noticed during the rising phase of pyrogen fever. There were no concomitant changes in blood PCO2 during that period of time. Although the concentrations of HCO3- were decreasing till the end of the experiment, the parallel falls in PCO2 led to a partial compensation of the noticed acidosis. Pretreatment with 200 mg/kg of sodium salicylate /an hour's iv infusion/reduced the febrile response by 42% and completely reversed the postpyrogen changes in pH and HCO3-. The falls in PCO2 during antipyresis, however, were similar to those observed in febrile rabbits. Possible mechanisms by which sodium salicylate could affect the pyrogen-induced disturbances of acid-base balance are being considered.
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36
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Dorward PK, Riedel W, Burke SL, Gipps J, Korner PI. The renal sympathetic baroreflex in the rabbit. Arterial and cardiac baroreceptor influences, resetting, and effect of anesthesia. Circ Res 1985; 57:618-33. [PMID: 4042286 DOI: 10.1161/01.res.57.4.618] [Citation(s) in RCA: 149] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Curves relating renal sympathetic nerve activity and mean arterial pressure were derived in conscious rabbits during ramp changes in mean arterial pressure, elicited by perivascular balloon inflation. The renal sympathetic nerve activity-mean arterial pressure relationship consisted of a high-gain sigmoidal region about resting, where renal sympathetic nerve activity rose or fell in response to moderate falls and rises of mean arterial pressure. With larger pressure rises, renal sympathetic nerve activity first fell to a lower plateau and then reversed at even higher mean arterial pressure. When mean arterial pressure was lowered below resting, renal sympathetic nerve activity rose to an upper plateau and then reversed abruptly toward resting at low mean arterial pressure. Both arterial and cardiac baroreceptors exerted substantial inhibitory influences on renal sympathetic nerve activity at all pressure levels. These effects appeared additive over the central high gain region of the curve, but beyond this region there were non-additive interactions. The latter were affected considerably by alfathesin anesthesia. In other experiments, we studied the effects of sustained alterations in resting mean arterial pressure induced by infusing nitroprusside and phenylephrine, which produced rapid resetting of the renal baroreflex. The latter could be accounted for, in part, by resetting of the threshold of the arterial baroreceptors and in part by contributions from other afferents, probably the cardiac receptors. During resetting associated with nitroprusside-induced falls in resting blood pressure, high-gain reflex adjustments in renal sympathetic nerve activity to moderate changes in mean arterial pressure were preserved, but during resetting associated with phenylephrine-induced rises in resting mean mean arterial pressure, the resting renal sympathetic nerve activity lay on the lower curve plateau, resulting in reduction in the apparent gain of the reflex renal sympathetic nerve activity response to moderate changes in mean arterial pressure.
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37
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Hashimoto M, Nagai M, Iriki M. Comparison of the action of prostaglandin with endotoxin on thermoregulatory response thresholds. Pflugers Arch 1985; 405:1-4. [PMID: 3903650 DOI: 10.1007/bf00591089] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Prostaglandin E2 (PGE2) and lipopolysaccharide (LPS) derived from E. coli were injected into the lateral cerebral ventricle of rabbits at 30 degrees C ambient temperature. The threshold core temperatures for ear cutaneous vasoconstriction (Thv) and shivering (Thsh) were determined by whole-body cooling with an intestinal thermode. Each threshold, as determined at the plateau phase of LPS fever and PGE2 hyperthermia respectively, were compared with the control values before LPS and PGE2 injection. Thsh was not changed by the injection of LPS, while Thv was increased. After PGE2 injection both Thsh and Thv were increased in comparison to their control levels. These changes paralleled the elevation of core temperature. The present study does not exclude prostaglandins as humoral mediators involved in some of the central processes generating fever, but suggest at the same time that there are additional properties of LPS fever for which prostaglandins do not account.
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38
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Riedel W. Ambient temperature modulates the differentiated cardiorespiratory pattern generated by the central noradrenergic system, most likely via alterations of thyrotropin-releasing hormone (TRH) activity. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1985; 12:145-57. [PMID: 3923090 DOI: 10.1016/0165-1838(85)90057-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In conscious rabbits with indwelling intracisternal (i.c.) catheters i.c. injections of 600 micrograms kg-1 6-hydroxydopamine (6-OHDA) elicited with short latencies an increase in metabolic rate followed by cutaneous vasoconstriction and a reduction in renal sympathetic nerve activity; in addition there was depression of respiratory rate, bradycardia and a fall of blood pressure. This differentiated cardiorespiratory activity pattern was fully established about 1 h after i.c. 6-OHDA, when injected at thermoneutrality. At warm ambient temperatures the metabolic and cardiorespiratory responses to i.c. 6-OHDA were considerably diminished and there was tachycardia. Intravenous (i.v.) injection of 4 micrograms kg-1 bacterial endotoxin (LPS) in intact rabbits evoked with short latency an increase in metabolic rate and the typical cardiorespiratory activity pattern normally seen in cold defense, consisting of cutaneous vasoconstriction, a depression of respiratory rate and, as shown in a previous study, a decrease in renal sympathetic nerve activity while heart rate and arterial blood pressure is little altered. When LPS was i.v. injected 2-3 days after i.c. 6-OHDA, the febrile response was attenuated with lesser cutaneous vasoconstriction and respiratory rate depression. There was no early inhibition in renal sympathetic nerve activity but rather marked excitation, with increases in heart rate and arterial blood pressure. The results indicate that the effects on autonomic system activities being produced by transmitter release at noradrenergic terminals acutely following i.c. 6-OHDA are considerably modulated by ambient temperature. Comparison of autonomic system reactions in fever obtained in the intact animal and after i.c. 6-OHDA reveals the important role of central noradrenergic pathways in preserving blood pressure homeostasis and heat conservation. The appearance of cardiorespiratory responses similar to those obtained after i.c. noradrenaline or i.c. 6-OHDA, when non-thermal activation of thyrotropin-releasing hormone (TRH) neurons occurs (as demonstrated in a previous study), suggests the hypothesis that TRH neurons known to be specifically influenced by changes in body temperature, converge onto the central noradrenergic system producing the typical cardiorespiratory pattern of cold defense.
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Klein W, Riedel W. Long-term recording of core temperatures with chronically implanted silicon diodes. Pflugers Arch 1985; 403:55-7. [PMID: 3982959 DOI: 10.1007/bf00583282] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
An electronic circuit for measurement of temperatures is described utilizing silicon diodes as temperature sensors and the feature that the reverse current flow of a diode is linearly related to temperature. Once calibrated and implanted into various sites of the body core of rabbits, the diodes preserved their precise temperature sensing qualities for periods longer than a year. Temperature changes of the atlanto-occipital membrane were found to be close to simultaneously measured intracisternal temperature, both temperatures being some 0.3 degree C higher than rectal temperature. This temperature-relationship persisted under conditions with different states of cutaneous vasoconstriction and thermal panting as observed in fever and during defervescence. These results indicate that extrahypothalamic brain regions as the cerebellum and the medulla oblongata do not benefit from the proposed protective function of brain cooling during stimulation of heat dissipating effector mechanisms.
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Cutaneous and renal blood flow changes during spinal cord thermal stimulation in 5-HT-depleted rabbits. J Therm Biol 1984. [DOI: 10.1016/0306-4565(84)90046-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Gagalo IT, Hać EE, Korolkiewicz KZ. The metabolic rate during the time course of salicylate antipyresis in the rabbit. Eur J Pharmacol 1983; 96:193-200. [PMID: 6426975 DOI: 10.1016/0014-2999(83)90308-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The processes concerned with the production and loss of body heat in sodium salicylate or acetylsalicylic acid antipyresis were investigated in adult rabbits at an ambient temperature of 21.5 +/- 0.5 degrees C. The experimental fever elicited by i.v. injection of lipopolysaccharide Escherichia coli (1 microgram/kg) was accompanied by increases in O2 consumption and CO2 production as well as decreases in convective heat loss. Pretreatment with 200 mg/kg of sodium salicylate (an hour's i.v. infusion) or with the same dose of acetylsalicylic acid (per os) significantly reduced pyrogen fever but the magnitude of O2 consumption and CO2 production remained at least at the febrile level. In the case of sodium salicylate, the level was even exceeded. At the same time both salicylates activated heat dissipation as manifested by decreases in vasomotor tone and tachypnea. Thus, it is apparent that the antipyretic effect of salicylates may develop without the inhibition of heat production. Heat loss processes initiated by these drugs are responsible for the antipyresis.
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Riedel W. Effect of propylthiouracil, and of bacterial endotoxin (LPS), on thyroid hormones, respiratory rate, cutaneous and renal blood flow in rabbits. Pflugers Arch 1983; 399:11-7. [PMID: 6359054 DOI: 10.1007/bf00652516] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Rabbits in a warm environment reacted to i.v. injections of 10 mg/kg propylthiouracil (PTU) with an immediate fall of serum triiodothyronine (T3) concentration, associated with decreases of respiratory rate and cutaneous blood flow. Simultaneously renal blood flow increased, while arterial blood pressure fell slightly. A rise in the animals' core temperature by 1.1 degree C, on average, contributed to the impression that PTU mimicked the stimulation of the normal thermoregulatory response pattern of cold defence. The cardiorespiratory responses to PTU were found to be augmented 6-8 days after thyroidectomy, but were completely abolished 16-20 days after thyroidectomy or chronic PTU treatment. In chronically thyroidectomized rabbits, i.v. injections of T3, but not of T4, elicited panting and cutaneous vasodilatation. The acute effects of injecting i.v. bacterial endotoxin (LPS) into rabbits in a warm environment consisted of cutaneous vasoconstriction and a decrease in respiratory rate, i.e. in an autonomic cold defence response, which was associated with a sustained increase in serum T3 concentration and caused core temperature, T3 serum concentration decreased again, whilst simultaneously the autonomic activity pattern changed to that of heat defence, comprising a rise in respiratory rate and skin vasodilatation. The results suggest the hypothesis that, similarly to a decrease of serum T3, LPS activates neurones in the CNS which secrete the thyrotropin-releasing hormone (TRH). This, in turn, elicits cardiorespiratory adjustments similar to those observed in the cold, while the opposite response occurs if these TRH secreting neurones are inhibited.
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Iriki M, Kozawa E. Renal sympathetic baroreflex during normoxia and during hypoxia in conscious and in anesthetized rabbits. Pflugers Arch 1983; 398:23-6. [PMID: 6889101 DOI: 10.1007/bf00584708] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The responses of renal sympathetic nerve activity (RSNA) to changes in mean arterial pressure (MAP) during normoxia and hypoxia was studied in conscious rabbits and during anesthesia with pentobarbitone (PB) by determining the RSNA baroreflex curves. In conscious rabbits, the gain in RSNA response was greater and the range of MAP between minimum and maximum levels of RSNA was narrower than in anesthetized rabbits. The renal sympathetic baroreflex was augmented by hypoxia, indicating a central excitatory interaction between the effects of baro- and chemoreceptor stimulation. However, hypoxia produced no significant change in median blood pressure. During anesthesia with PB, resting MAP was decreased, median blood pressure was lowered, and renal sympathetic baroreflexes were less pronounced. Renal sympathetic baroreflex was augmented by hypoxia, and there was a significant increase in median blood pressure. These results provide direct evidence of an inhibitory effect of PB on the response of RSNA to baro- and chemoreceptor stimulation.
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Riedel W, Hales J. Prostaglandins modify tissue blood flow and respiratory rate in febrile rabbits. J Therm Biol 1983. [DOI: 10.1016/0306-4565(83)90104-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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