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Relationship of MTT reduction to stimulants of muscle metabolism

Citation

Newman, JMB and DiMaria, CA and Rattigan, S and Steen, JT and Miller, KAL and Eldershaw, TPD and Clark, MG, Relationship of MTT reduction to stimulants of muscle metabolism, Chemico-Biological Interactions, 128, (2) pp. 127-140. ISSN 0009-2797 (2000) [Refereed Article]

DOI: doi:10.1016/S0009-2797(00)00192-7

Abstract

MTT, a positively charged tetrazolium salt, is widely used as an indicator of cell viability and metabolism and has potential for histochemical identification of tissue regions of hypermetabolism. In the present study, MTT was infused in the constant-flow perfused rat hindlimb to assess the effect of various agents and particularly vasoconstrictors that increase muscle metabolism. Reduction of MTT to the insoluble formazan in muscles assessed at the end of experiments was linear over a 30 min period and production rates were greater in red fibre types than white fibre types. The vasoconstrictors, norepinephrine (100 nM) and angiotensin (10 nM) decreased MTT formazan production in all muscles but increased hindlimb oxygen uptake and lactate efflux. Veratridine, a Na + channel opener that increases hindlimb oxygen uptake and lactate efflux without increases in perfusion pressure, also decreased MTT formazan production. Membrane stabilizing doses (100 μM) of (±)-propranolol reversed the inhibitory effects of angiotensin and veratridine on MTT formazan production. Muscle contractions elicited by stimulation of the sciatic nerve, reversed the norepinephrine-mediated inhibitory effects on MTT formazan production, even though oxygen consumption and lactate efflux were further stimulated. Stimulation of hindlimb muscle oxygen uptake by pentachlorophenol, a mitochondrial uncoupler, was not associated with alterations in MTT formazan production. It is concluded that apart from muscle contractions MTT formazan production does not increase with increased muscle metabolism. Since the vasoconstrictors angiotensin and norepinephrine as well as veratridine activate Na + channels and the Na +/K + pump, energy required for Na + pumping may be required for MTT reduction. It is unlikely that vasoconstrictors that stimulate oxygen uptake do so by uncoupling respiration. (C) 2000 Elsevier Science Ireland Ltd.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Biochemistry and Cell Biology
Research Field:Cell Metabolism
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Environmental Sciences
Author:Newman, JMB (Dr John Newman)
Author:DiMaria, CA (Ms Carla Alexandra DiMaria)
Author:Rattigan, S (Professor Stephen Rattigan)
Author:Steen, JT (Dr John Steen)
Author:Miller, KAL (Ms Miller)
Author:Eldershaw, TPD (Mr Tristram Eldershaw)
Author:Clark, MG (Professor Michael Clark)
ID Code:19320
Year Published:2000
Web of Science® Times Cited:5
Deposited By:Biochemistry
Deposited On:2000-08-01
Last Modified:2011-09-29
Downloads:0

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