Tamaki T, Shiraishi T
Department of Physiology, Tokai University School of Medicine, Kanagawa, Japan.
Anat Rec. 1996 Nov;246(3):335-42. doi: 10.1002/(SICI)1097-0185(199611)246:3<335::AID-AR4>3.0.CO;2-X.
We reported that numerous complex branched fibers (CBF) are present in the compensatory hypertrophied plantaris muscle prepared by surgical removal of the synergist muscles in the rat. To investigate the functional effects of these CBF, we examined the histochemical and contractile properties of this muscle.
Compensatory hypertrophied plantaris (PLA) muscles were prepared by ipsilateral ablation of synergistic muscle in male Wistar rats. We compared the operated (OP), contralateral (CON-L), and nonoperated age-matched normal control (NOR-C) plantaris muscles. Contractile properties under urethane anesthesia and histochemical properties (myofibrillar ATPase staining) were examined at 6, 10, and 15 weeks after surgical preparation of the muscles.
The weight of the OP muscle was 48-55% higher than that of the CON-L muscle. The twitch-time-to-peak tension (TPT) and half-relaxation time (HRT) were slower in NOR-C < CON-L < OP. The shift to slower muscle characteristics was also associated with a similar order (NOR-C < CON-L < OP) of histochemical analysis. However, the fatigue resistance capacity of OP (time to 50% fall in tension from initial peak tension during 15-Hz twitch train) was less than that of CON-L, in contrast to the results of twitch, tetanus, and histochemical analysis. The order of NOR-C < CON-L < OP was not observed in the fatigue-resistance test.
Our results suggest that the presence of CBF may disturb the correlation between histochemical and functional properties of the whole muscle. In addition, the CON-L muscle clearly shifted to slower muscle characteristics, indicating that it was not similar to normal control muscle.
我们报道过，在通过手术切除大鼠协同肌而制备的代偿性肥大的比目鱼肌中存在大量复杂分支纤维（CBF）。为了研究这些CBF的功能作用，我们检测了该肌肉的组织化学和收缩特性。
通过对雄性Wistar大鼠同侧协同肌进行切除来制备代偿性肥大的比目鱼肌（PLA）。我们对比了手术侧（OP）、对侧（CON-L）以及未手术的年龄匹配正常对照（NOR-C）比目鱼肌。在肌肉手术制备后的6周、10周和15周，检测了在乌拉坦麻醉下的收缩特性以及组织化学特性（肌原纤维ATP酶染色）。
OP肌肉的重量比CON-L肌肉高48%-55%。单收缩达到峰值张力的时间（TPT）和半松弛时间（HRT）在NOR-C < CON-L < OP中逐渐变慢。肌肉特性向更慢转变也与组织化学分析的相似顺序（NOR-C < CON-L < OP）相关。然而，与单收缩、强直收缩和组织化学分析结果相反，OP的抗疲劳能力（在15赫兹单收缩串刺激期间张力从初始峰值张力下降50%的时间）小于CON-L。在抗疲劳试验中未观察到NOR-C < CON-L < OP的顺序。
我们的结果表明，CBF的存在可能会干扰整块肌肉组织化学和功能特性之间的相关性。此外，CON-L肌肉明显向更慢的肌肉特性转变，表明它与正常对照肌肉不同。
