Premium
Experimental investigation of thermal effects in skeletal muscle: tetanic and post‐tetanic potentiation
Author(s) -
Barnes William Stephen
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.801.10
Subject(s) - tetanic stimulation , chemistry , stimulation , post tetanic potentiation , long term potentiation , contraction (grammar) , muscle contraction , anatomy , medicine , biochemistry , biology , receptor
Force production in striated muscle is influenced by temperature, as are most physiological processes. The purpose of this investigation was to determine what effect altering incubation temperature might have on force output before and after brief periods of tetanic stimulation. Sartorii muscles (60–70 mg) from R. pipiens were dissected‐free and vertically‐mounted in water‐jacketed chambers containing oxygenated (100%), Ringer solution (pH 7.2; 20°C). To determine peak twitch tension (PT, g) at different temperatures (10°–30°C), muscles were stimulated via supramaximal square wave pulses (0.2 ms) every 10 s for 2 min before and after a 2.5 s tetanic contraction (80 Hz). Averaged PT immediately preceding tetanic stimulation was 25.2 ± 2.7, 18.1 ± 2.2 and 14.1 ± 0.9 at 10°C, 20°C and 30°C, respectively. Corresponding thermal ratios (R 10 ) were 0.72 (10°–20°C) and 0.78 (20°–30°C). Peak tetanic tensions (PTT, g) and tension‐time integrals (TTI, g·s) were 47.3 ± 4.7, 60.1 ± 6.5, and 49.4 ± 5.8, and 100.9 ± 6.8, 140.4 ± 17.0 and 107.4 ±16.1 at 10°C, 20°C and 30°C, respectively. Averaged PT immediately following tetanic stimulation was 27.2 ± 2.1, 25.1 ± 0.7, and 15.4 ± 0.6 at 10°C, 20°C and 30°C, respectively. R 10 values were 0.92 (10°–20°C) and 0.61 (20°–30°C). These results suggest that variations in the thermal environment may significantly mediate force output and alter the efficacy of neuro‐motor control mechanisms.