PROPERTIES ENHANCING AEROBIC CAPACITY OF CALLING MUSCLES IN GRAY TREE FROGS HYLA-VERSICOLOR
PROPERTIES ENHANCING AEROBIC CAPACITY OF CALLING MUSCLES IN GRAY TREE FROGS HYLA-VERSICOLOR
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DOI：
10.1152/ajpregu.1987.252.4.r786
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发表时间：
1987-04-01
影响因子：
--
通讯作者：
TAIGEN, TL
中科院分区：
文献类型：
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作者：
MARSH, RL;TAIGEN, TL
研究人员检查了适应灰树蛙雨蛙（Hyla versicolor）过程中极高有氧呼吸的肌肉特征。我们将雄性用于叫声的肌肉（耳外肌、内耳肌和喉肌）与雌性的同源肌肉以及雄性和雌性的腿部肌肉进行了比较。腿部肌肉由 75% 体积的快速糖酵解纤维组成，这是无尾两栖动物中描述的其他肌肉的典型成分。相比之下，雄性的呼叫肌肉由 100% 快速氧化纤维组成，柠檬酸合酶 (CS) 活性在变温脊椎动物中最高，为 65-80 .mu.mol .cntdot。 min-1 .cntdot。 g新鲜质量-1。我们还注意到这些肌肉的大小和氧化能力存在强烈的性别二态性。女性的腹外斜肌和腹内斜肌的重量比男性相应的肌肉轻一个数量级，并且CS活性仅为6.mu.mol.cntdot。 min-1 .cntdot。 g-1。透射电子显微照片的形态测量显示，与代表性的后肢肌肉相比，雄性的呼叫肌肉含有高线粒体密度（约纤维体积的 20%）和毛细血管密度（约 700 mm-2）；毛细管密度，230 mm-2)。这些青蛙肌肉的工作频率为 .apprx。 20度。 C，单位线粒体体积的毛细血管密度低于在较高温度下发挥作用的哺乳动物肌肉中的毛细血管密度。
The muscle features that accomodate the extraordinary high aerobic features that accomodate the extraordinarily high aerobic respiration during calling y the gray tree frog Hyla versicolor were examined. We compared the muscles used for calling by males (external and internal olbiues and laryngeal muscles) with the homologous muscles of females and with the leg muscles of males and females. The leg muscles consisted of 75% by volume fast glycolytic fibers, a composition typical of other muscles described in anuran amphibians. In contrast the calling muscles of males consisted of 100% fast oxidative fibers and had citrate synthase (CS) activities among the highest recorded for ectothermic vertebrates, 65-80 .mu.mol .cntdot. min-1 .cntdot. g fresh mass-1. We also noted a strong sexual dimorphism in size and oxidative capacity of these muscles. The external and internal obliques of females weighed an order of magnitude less than the corresponding muscles of males and had CS activities of only 6 .mu.mol .cntdot. min-1 .cntdot. g-1. Morphometric measurements of transmission electron micrographs revealed that the calling muscles of males contained high mitochondrial densities (.apprx. 20% of fiber volume) and capillary densities (.apprx. 700 mm-2) compared with a representative hindlimb muscle; capillary density, 230 mm-2). These frog muscles, which operate at .apprx. 20.degree. C, have lower capillary densities per mitochondrial volume than are found in mammalian muscles that function at higher temperatures.