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Dunstan R, Sparkes D, Dascombe B, Evans C, Macdonald M, Crompton M, Franks J, Murphy G, Gottfries J, Carlton B, Roberts T. Sweat facilitated losses of amino acids in Standardbred horses and the application of supplementation strategies to maintain condition during training. COMPARATIVE EXERCISE PHYSIOLOGY 2015. [DOI: 10.3920/cep150027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Little is known about the amino acid composition of horse sweat, but significant fluid losses can occur during exercise with the potential to facilitate substantial nutrient losses. Sweat and plasma amino acid compositions for Standardbred horses were assessed to determine losses during a standardised training regime. Two cohorts of horses 2013 (n=5) and 2014 (n=6) were assessed to determine baseline levels of plasma and sweat amino acids. An amino acid supplement designed to counter losses in sweat during exercise was provided after morning exercise daily for 5 weeks (2013, n=5; 2014, n=4). After the supplementation period, blood and sweat samples were collected to assess amino acid composition changes. From baseline assessments of sweat in both cohorts, it was found that serine, glutamic acid, histidine and phenylalanine were present at up to 9 times the corresponding plasma concentrations and aspartic acid at 0-2.2 μmol/l in plasma was measured at 154-262 μmol/l in sweat. In contrast, glutamine, asparagine, methionine and cystine were conserved in the plasma by having lower concentrations in the sweat. The predominant plasma amino acids were glycine, glutamine, alanine, valine, serine, lysine and leucine. As the sweat amino acid profile did not simply reflect plasma composition, it was proposed that mechanisms exist to generate high concentrations of certain amino acids in sweat whilst selectively preventing the loss of others. The estimated amino acid load in 16 l of circulating plasma was 3.8-4.3 g and the calculated loss via sweat during high intensity exercise was 1.6-3.0 g. Following supplementation, total plasma amino acid levels from both cohorts increased from initial levels of 2,293 and 2,044 µmol/l to post-supplementation levels of 2,674 and 2,663 µmol/l respectively (P<0.05). It was concluded that the strategy of providing free amino acids immediately after exercise resulted in raising resting plasma amino acid levels.
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Affiliation(s)
- R.H. Dunstan
- University of Newcastle, School of Environmental and Life Sciences, University Dr, Callaghan, NSW 2308, Australia
| | - D.L. Sparkes
- University of Newcastle, School of Environmental and Life Sciences, University Dr, Callaghan, NSW 2308, Australia
| | - B.J. Dascombe
- University of Newcastle, School of Environmental and Life Sciences, 10 Chittaway Road, Ourimbah, NSW 2258, Australia
| | - C.A. Evans
- University of Newcastle, School of Environmental and Life Sciences, University Dr, Callaghan, NSW 2308, Australia
| | - M.M. Macdonald
- University of Newcastle, School of Environmental and Life Sciences, University Dr, Callaghan, NSW 2308, Australia
| | - M. Crompton
- University of Newcastle, School of Environmental and Life Sciences, University Dr, Callaghan, NSW 2308, Australia
| | - J. Franks
- University of Newcastle, School of Environmental and Life Sciences, University Dr, Callaghan, NSW 2308, Australia
| | - G. Murphy
- University of Newcastle, School of Environmental and Life Sciences, University Dr, Callaghan, NSW 2308, Australia
| | - J. Gottfries
- Department of Chemistry, University of Gothenburg, P.O. Box 100, 405 30 Gothenburg, Sweden
| | - B. Carlton
- University of Newcastle, School of Environmental and Life Sciences, University Dr, Callaghan, NSW 2308, Australia
| | - T.K. Roberts
- University of Newcastle, School of Environmental and Life Sciences, University Dr, Callaghan, NSW 2308, Australia
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3
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Sullivan SL, Cudmore LA, Bacci BB, Tennent-Brown BS. Atypical histopathological findings in a 15-year-old Warmblood gelding diagnosed with anhidrosis in a temperate climate. EQUINE VET EDUC 2015. [DOI: 10.1111/eve.12208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - L. A. Cudmore
- University of Melbourne; Werribee Victoria Australia
| | - B. B. Bacci
- University of Melbourne; Werribee Victoria Australia
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4
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MacKay RJ, Mallicote M, Hernandez JA, Craft WF, Conway JA. A review of anhidrosis in horses. EQUINE VET EDUC 2014. [DOI: 10.1111/eve.12220] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- R. J. MacKay
- Department of Large Animal Clinical Sciences; University of Florida; Gainesville USA
| | - M. Mallicote
- Department of Large Animal Clinical Sciences; University of Florida; Gainesville USA
| | - J. A. Hernandez
- Department of Large Animal Clinical Sciences; University of Florida; Gainesville USA
| | - W. F. Craft
- Department of Infectious Diseases & Pathology; University of Florida; Gainesville USA
| | - J. A. Conway
- Department of Infectious Diseases & Pathology; University of Florida; Gainesville USA
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5
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Abstract
The condition of anhidrosis is described in this review, and the latest theories on the causal factors are explored. The evidence supports the hypothesis that anhidrosis is an inappropriate response to prolonged climatic stress (generally combined heat and high humidity), which can be evoked in a small (approximately 10 +/- 5%) proportion of the equine population. It is caused by gradual failure of the glandular secretory cell processes, initiated by desensitization and subsequent down-regulation of the cell receptors as a result of continued adrenaline-driven hyperactivity. It progresses through secretory failure and culminates in gradual, probably irreversible, glandular dedifferentiation and ultimate degeneration. There is a need for considerably more research on the secretory and transcriptional processes to document the changes arising within the glandular secretory mechanism as a prelude to development of a corrective treatment.
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Affiliation(s)
- David McEwan Jenkinson
- Institute of Biomedical and Life Sciences, West Medical Building, University of Glasgow, Glasgow G12 8QQ, UK
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6
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Abstract
The molecular basis of the pathophysiology of anhidrosis is still not well understood. Therefore, treatments are more often based on clinical impressions than on scientific fact. Treatment options for this condition will improve only when more is known about the molecular events that cause anhidrosis, especially as they relate to beta2-receptor dysfunction and stimulus-secretion coupling in the sweat glands of affected horses. Although this additional information is being attained, sound environmental management will continue to be a very important aspect of the treatment of horses affected with anhidrosis.
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Affiliation(s)
- Jeremy D Hubert
- School of Veterinary Medicine, Department of Veterinary Clinical Sciences, Equine Health Studies Program, Louisiana State University, Baton Rouge, LA 70803, USA.
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7
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Scott CM, Marlin DJ, Schroter RC. Quantification of the response of equine apocrine sweat glands to beta2-adrenergic stimulation. Equine Vet J 2001; 33:605-12. [PMID: 11720033 DOI: 10.2746/042516401776563463] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The aim of the present study was to characterise the quantitative sweating response of the horse to beta2-adrenergic stimulation. The sweating responses of 6 horses to the randomised infusion of 8 different adrenaline concentrations (0.025, 0.05, 0.075, 0.1, 0.2, 0.4, 1.0 or 2.0 microg/kg bwt/min), was investigated. Sweating rate (SR) and skin temperature (TSK) on the neck (N) and gluteal region (G), and plasma adrenaline and noradrenaline concentrations were measured. Peak SR was approximately 15 (N) and approximately 9 g/m2/min (G) during infusion of both 1.0 and 2.0 microg/kg bwt/min adrenaline. Sweat produced per nmol/l plasma adrenaline peaked during the infusion of 0.075 microg/kg bwt/min adrenaline. Higher adrenaline infusion concentrations resulted in a progressive decrease in the amount of sweat produced per nmol/l plasma adrenaline and a plateau of 6 g/m2/(nmol/l) plasma adrenaline was reached for infusions between 1.0 and 2.0 microg/kg bwt/min. Peak SR were far lower than we have previously reported during exercise. There was no evidence of sweat gland fatigue or vasoconstriction during infusion, suggesting saturation of sweat gland beta2 receptors. We conclude that sweating in the horse is under dual control from a combination of hormonal and neural mechanisms.
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Affiliation(s)
- C M Scott
- Centre for Equine Studies, The Animal Health Trust, Kentford, Newmarket, Suffolk, UK
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15
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Abstract
1. Donkeys sweat on exposure to heat and in response to intravenous adrenaline infusion.2. Thermal sweating was abolished by the adrenergic-neurone blocking agent bethanidine but not by atropine.3. Sympathetic decentralization (by preganglionic sympathectomy) abolished thermal sweating but adreno-medullary denervation had no effect.4. Exercise resulted in sweating from both sympathetically innervated and decentralized skin and from the innervated skin of animals which had previously undergone adreno-medullary denervation.5. Insulin-induced hypoglycaemia resulted in sweating from sympathetically decentralized skin and from innervated skin in two out of four animals. Adreno-medullary denervation abolished the sweat gland response to insulin administration.6. Cold exposure inhibited the response of innervated sweat glands but not that of decentralized glands to adrenaline infusion.7. It was concluded that heat-induced and exercise-induced sweating of the donkey is controlled by adrenergic nerves; adreno-medullary secretion may contribute to sweating during exercise, and that cutaneous blood flow is important in the response of the glands to humoral stimulation.
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23
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KUNO Y, YAMADA T, OHARA K. A Preliminary Note on the Humoral Sweat Secretion in Human Caused by Adrenaline. ACTA ACUST UNITED AC 1962. [DOI: 10.2183/pjab1945.38.227] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Yas KUNO
- Department of Physiology, Kyoto Prefectural Medical University
| | - Toshio YAMADA
- Department of Physiology, Kyoto Prefectural Medical University
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