Metabolism of perfused pig intercostal muscles evaluated by 31P-magnetic resonance spectroscopy.

TY - JOUR

T1 - Metabolism of perfused pig intercostal muscles evaluated by 31P-magnetic resonance spectroscopy.

AU - Pedersen, Brian Lindegaard

AU - Arendrup, Henrik

AU - Secher, Niels H

AU - Quistorff, Bjørn

N1 - Keywords: Adenosine Diphosphate; Adenosine Triphosphate; Animals; Energy Metabolism; Intercostal Muscles; Magnetic Resonance Spectroscopy; Metabolic Clearance Rate; Models, Animal; Muscle Contraction; Muscle, Skeletal; Oxygen; Oxygen Consumption; Perfusion; Phosphorus Isotopes; Swine

PY - 2006

Y1 - 2006

N2 - This study presents a perfused preparation for evaluation of metabolism in pig intercostal muscle in vitro. Preserved vessels and nerves to an intercostal segment including two adjacent ribs allowed for tissue perfusion and electrical stimulation with measurement of contraction force, oxygen consumption and 31P-magnetic resonance spectroscopy (31P-MRS). When perfused at rest with Krebs-Ringer buffer, the preparation maintained physiological levels of phosphocreatine (PCr), inorganic phosphate (Pi), ATP and pH at a stable oxygen consumption of 0.51 +/- 0.01 micromol min(-1) g(-1) for more than 2 h. Tonic stimulation of the nerve caused anaerobic energy consumption as PCr and pH decreased, and both variables recovered after the contraction with half-time values of approximately 7 min. Force increased to 0.040 N g(-1) (range, 0.031-0.103 N g(-1)) and it gradually decreased by about 70% during the subsequent 5 min of stimulation. The calculated free ADP concentration increased from 7.4 +/- 2.1 nmol g(-1) at rest to 28 +/- 12 nmol g(-1) (mean +/- s.d.) by the end of the stimulation. Thus anaerobic ATP turnover was zero at rest, 6.1 +/- 2 micromol min(-1) g(-1) during the first minute of stimulation and 3.5 +/- 0.5 micromol min(-1) g(-1) during the two last minutes, corresponding to the drop in force. When the preparation was left unperfused, anaerobic ATP turnover averaged 0.40 +/- 0.15 micromol min(-1) g(-1) for the first 10 min. The preparation can also be applied to human intercostal muscles, as demonstrated in one preliminary experiment. The results demonstrate a stable and functional in vitro preparation of intact perfused intercostal muscles in the pig.

AB - This study presents a perfused preparation for evaluation of metabolism in pig intercostal muscle in vitro. Preserved vessels and nerves to an intercostal segment including two adjacent ribs allowed for tissue perfusion and electrical stimulation with measurement of contraction force, oxygen consumption and 31P-magnetic resonance spectroscopy (31P-MRS). When perfused at rest with Krebs-Ringer buffer, the preparation maintained physiological levels of phosphocreatine (PCr), inorganic phosphate (Pi), ATP and pH at a stable oxygen consumption of 0.51 +/- 0.01 micromol min(-1) g(-1) for more than 2 h. Tonic stimulation of the nerve caused anaerobic energy consumption as PCr and pH decreased, and both variables recovered after the contraction with half-time values of approximately 7 min. Force increased to 0.040 N g(-1) (range, 0.031-0.103 N g(-1)) and it gradually decreased by about 70% during the subsequent 5 min of stimulation. The calculated free ADP concentration increased from 7.4 +/- 2.1 nmol g(-1) at rest to 28 +/- 12 nmol g(-1) (mean +/- s.d.) by the end of the stimulation. Thus anaerobic ATP turnover was zero at rest, 6.1 +/- 2 micromol min(-1) g(-1) during the first minute of stimulation and 3.5 +/- 0.5 micromol min(-1) g(-1) during the two last minutes, corresponding to the drop in force. When the preparation was left unperfused, anaerobic ATP turnover averaged 0.40 +/- 0.15 micromol min(-1) g(-1) for the first 10 min. The preparation can also be applied to human intercostal muscles, as demonstrated in one preliminary experiment. The results demonstrate a stable and functional in vitro preparation of intact perfused intercostal muscles in the pig.

U2 - 10.1113/expphysiol.2006.033274

DO - 10.1113/expphysiol.2006.033274

M3 - Journal article

C2 - 16675500

SN - 0958-0670

VL - 91

SP - 755

EP - 763

JO - Experimental Physiology

JF - Experimental Physiology

IS - 4

ER -