McLister D, Stevens E D, Bogart J P
Department of Zoology, University of Guelph, Ontario, Canada.
J Exp Biol. 1995 Jul;198(Pt 7):1527-38. doi: 10.1242/jeb.198.7.1527.
Isometric twitch and tetanus parameters, force-velocity curves, maximum shortening velocity (Vmax) and percentage relaxation between stimuli (%R) across a range of stimulus frequencies were determined for a muscle used during call production (the tensor chordarum) and a locomotor muscle (the sartorius) for three species of hylid frogs, Hyla chrysoscelis, H. versicolor and H. cinerea. The call of H. chrysoscelis has a note repetition rate (NRR) approximately twice as fast as the call of H. versicolor (28.3, 42.5 and 56.8 notes s-1 for H. chrysoscelis and 14.8, 21.1 and 27.4 notes s-1 for H. versicolor at 15, 20 and 25 degrees C, respectively). Hyla cinerea calls at a very slow NRR (Approximately 3 notes s-1 at 25 degrees C). Hyla versicolor evolved from H. chrysoscelis via autopolyploidy, so the mating call of H. chrysoscelis is presumably the ancestral mating call of H. versicolor. For the tensor chordarum of H. chrysoscelis, H. versicolor and H. cinerea at 25 degrees C, mean twitch duration (19.2, 30.0 and 52.9 ms, respectively), maximum isometric tension (P0; 55.0, 94.4 and 180.5 kN m-2, respectively), tetanic half-relaxation time (17.2, 28.7 and 60.6 ms, respectively) and Vmax (4.7, 5.2 and 2.1 lengths s-1, respectively) differed significantly (P < 0.05) among all three species. The average time of tetanic contraction to half-P0 did not differ significantly between H. chrysoscelis (14.5 ms) and H. versicolor (15.8 ms) but was significantly longer for H. cinerea (52.6 ms). At 25 degrees C, Vmax differed significantly among the sartorius muscles of H. chrysoscelis, H. versicolor and H. cinerea (5.2, 7.0 and 9.8 lengths s-1, respectively) but mean twitch duration (29.5, 32.2 and 38.7 ms, respectively), P0 (252.2, 240.7 and 285.1 kN m-2, respectively) and tetanic half-relaxation time (56.3, 59.5 and 60.7 ms, respectively) did not differ significantly. The average time of contraction to half-P0 did not differ significantly between H. chrysoscelis (23.7 ms) and H. versicolor (22.9 ms) but was significantly shorter for H. cinerea (15.6 ms). The only consistent contractile differences found in this study between the calling muscle and locomotor muscle of H. chrysoscelis, H. versicolor and H. cinerea were that the calling muscles generated less tension and their force-velocity relationship was much more linear. These differences may be attributable to ultrastructural differences between calling and locomotor muscles.(ABSTRACT TRUNCATED AT 400 WORDS)
测定了三种雨蛙（金黄雨蛙、变色雨蛙和灰雨蛙）用于发声的肌肉（声带张肌）和运动肌肉（缝匠肌）在一系列刺激频率下的等长收缩和强直收缩参数、力-速度曲线、最大缩短速度（Vmax）以及刺激间的放松百分比（%R）。金黄雨蛙的叫声音符重复率（NRR）大约是变色雨蛙的两倍（在15、20和25摄氏度时，金黄雨蛙的NRR分别为28.3、42.5和56.8次/秒，变色雨蛙分别为14.8、21.1和27.4次/秒）。灰雨蛙的叫声NRR非常慢（在25摄氏度时约为3次/秒）。变色雨蛙是通过同源多倍体从金黄雨蛙进化而来的，所以金黄雨蛙的求偶叫声大概是变色雨蛙的祖先求偶叫声。在25摄氏度时，金黄雨蛙、变色雨蛙和灰雨蛙的声带张肌，平均收缩持续时间（分别为19.2、30.0和52.9毫秒）、最大等长张力（P0；分别为55.0、94.4和180.5千牛/平方米）、强直半松弛时间（分别为17.2、28.7和60.6毫秒）和Vmax（分别为4.7、5.2和2.1体长/秒）在所有三个物种之间均有显著差异（P < 0.05）。金黄雨蛙（14.5毫秒）和变色雨蛙（15.8毫秒）的强直收缩到半P0的平均时间没有显著差异，但灰雨蛙（52.6毫秒）的显著更长。在25摄氏度时，金黄雨蛙、变色雨蛙和灰雨蛙的缝匠肌Vmax有显著差异（分别为5.2、7.0和9.8体长/秒），但平均收缩持续时间（分别为29.5、32.2和38.7毫秒）、P0（分别为252.2、240.7和285.1千牛/平方米）和强直半松弛时间（分别为56.3、59.
