| Heat acclimation in rats: modulation via lipid polyunsaturation. | |
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MedLine Citation:
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PMID: 12121852 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Heat acclimation of rats has been shown to enhance endurance of rat hearts to ischemic insult and acute heat stress. Common protective features have been shown to be operative during both these stress-inducing conditions. To explore the role of membrane lipid composition in the adaptive response, we analyzed two major parameters that impact membrane dynamics and order, the nonesterified cholesterol levels and the acyl chain composition of phospholipids, in rat heart and salivary glands, both major thermoregulatory organs, in short- and long-term heat-acclimated rats. Before exposure to heat, control salivary gland tissue has a higher cholesterol-to-phospholipid mole ratio (0.32 +/- 0.02) than heart (0.14 +/- 0.01), and the acyl chains of its phospholipids are 50% more saturated. The remodeling strategies of the tissues after exposure to heat differed. Heart cholesterol levels increased after short-term heat acclimation (approximately 50%), whereas salivary gland cholesterol levels decreased in acute heat stress and long-term heat acclimation (approximately 32%). Remodeling of phospholipid acyl chains, particularly an increase in docosahexaenoic acid, was a protective strategy in both tissues (57% in heart and >100% in salivary glands). Modifying membrane lipid composition by treating rats with liposomes composed of egg phosphatidylcholine (PC) before exposure to heat resulted in a 38% increase in endurance to thermal stress. The density and affinity of muscarinic receptors of submaxillary salivary glands, involved in the acclimation response, were measured in control and PC liposome-treated rats, and then both groups were subjected to short-term heat acclimation. After PC treatment the well-established compensatory upregulation of the muscarinic receptors and concomitant decrease in their affinity was blunted. The substantial increase in the thermal endurance of heat-challenged intact rats after treatment with PC liposomes (600 vs. 200 min) suggests that membrane lipid composition plays a role in the ability of these tissues to respond to heat stress. |
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Authors:
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Hilary Shmeeda; Pavel Kaspler; Judith Shleyer; Reuma Honen; Michal Horowitz; Yechezkel Barenholz |
Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: American journal of physiology. Regulatory, integrative and comparative physiology Volume: 283 ISSN: 0363-6119 ISO Abbreviation: Am. J. Physiol. Regul. Integr. Comp. Physiol. Publication Date: 2002 Aug |
Date Detail:
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Created Date: 2002-07-17 Completed Date: 2002-08-15 Revised Date: 2003-11-14 |
Medline Journal Info:
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Nlm Unique ID: 100901230 Medline TA: Am J Physiol Regul Integr Comp Physiol Country: United States |
Other Details:
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Languages: eng Pagination: R389-99 Citation Subset: IM |
Affiliation:
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Department of Biochemistry, The Hebrew University, Hadassah Medical School, Jerusalem 91120, Israel. hilary@szmc.org.il |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adaptation, Physiological
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drug effects,
physiology* Animals Cholesterol / analysis, metabolism Docosahexaenoic Acids / analysis, metabolism Fatty Acids, Unsaturated / chemistry, metabolism* Heat Stress Disorders / drug therapy, metabolism* Liposomes Male Membrane Lipids / chemistry, metabolism* Myocardium / chemistry, metabolism Phosphatidylcholines / administration & dosage, pharmacology Phospholipids / chemistry, metabolism Rats Receptors, Muscarinic / metabolism Salivary Glands / chemistry, metabolism |
| Chemical | |
Reg. No./Substance:
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0/Fatty Acids, Unsaturated; 0/Liposomes; 0/Membrane Lipids; 0/Phosphatidylcholines; 0/Phospholipids; 0/Receptors, Muscarinic; 25167-62-8/Docosahexaenoic Acids; 57-88-5/Cholesterol |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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