IDENTIFICATION OF INTRAFUSAL MUSCLE-FIBERS ACTIVATED BY SINGLE FUSIMOTOR AXONS AND INJECTED WITH FLUORESCENT DYE IN CAT TENUISSIMUS SPINDLES
IDENTIFICATION OF INTRAFUSAL MUSCLE-FIBERS ACTIVATED BY SINGLE FUSIMOTOR AXONS AND INJECTED WITH FLUORESCENT DYE IN CAT TENUISSIMUS SPINDLES
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DOI：
10.1113/jphysiol.1978.sp012182
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发表时间：
1978-01-01
影响因子：
5.5
通讯作者：
STACEY, MJ
中科院分区：
文献类型：
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作者：
BARKER, D;BESSOU, P;STACEY, MJ
将荧光染料Procion Huang[PY]注入猫细长肌梭内肌纤维，记录其在1/S单次静态或动态γ刺激时膜电位的变化，进行组织学鉴定。轴突。梭内肌纤维(13)由静电伽马支配。轴突为8根bag2纤维和5根链状纤维。未发现Bag1纤维。在1个纺锤中，将PY注射到由相同静电伽马激活的2个梭内肌纤维中。轴突；它们被鉴定为Bag2和链状纤维。9条梭内肌纤维由动态伽马神经支配。轴突由7根bag1纤维、1根bag2纤维和1根长链纤维组成。在1个纺锤中，2个袋状纤维被注入，1个被动态伽马激活。一个是轴突，另一个是静电伽马。前者明显为bag1纤维，后者为bag2纤维。静电伽马的刺激。轴突在7个bag2纤维和1个受损的链纤维中诱发连接电位，在1个bag2和4个链纤维中诱发动作电位。在被静态轴突激活的梭内肌纤维标本中，23例(62.2%)记录到连接电位，14例(37.8%)记录到动作电位。对动态伽马的刺激。轴突总是能激发连接电位。运动终末的超微结构属于受刺激的γ。对轴突进行检查。由静态伽马提供的尾端的肌神经连接。至bag2和链状纤维的轴突光滑并折叠，最深和最规则的折叠发生在链状纤维上。由动态伽马提供给Bag1纤维的P2板的端子。轴突有光滑的肌神经连接。
Intrafusal muscle fibers of cat tenuissimus spindles were injected with the fluorescent dye Procion Yellow [PY] and identified histologically after recording their changes in membrane potential during 1/s stimulation of single static or dynamic .gamma. axons. Intrafusal muscle fibers (13) innervated by static .gamma. axons were identified as 8 bag2 and 5 chain fibers. No bag1 fibers were identified. In 1 spindle PY was injected into 2 intrafusal muscle fibers activated by the same static .gamma. axon; they were identified as a bag2 and a chain fiber. Nine intrafusal muscle fibers innervated by dynamic .gamma. axons were identified as seven bag1 fibers, 1 bag2 fiber and 1 long chain fiber. In 1 spindle 2 bag fibers were injected, 1 activated by a dynamic .gamma. axon, the other by a static .gamma. axon; the former apparently was a bag1 fiber, the latter a bag2 fiber. Stimulation of static .gamma. axons elicited junctional potentials in 7 bag2 fibers and 1 damaged chain fiber and action potentials in 1 bag2 and 4 chain fibers. In the whole sample of impaled intrafusal muscle fibers (identified and unidentified) activated by static axons, junctional potentials were recorded from 23 (62.2%) and action potentials from 14 (37.8%). Stimulation of dynamic .gamma. axons always elicited junctional potentials. The ultrastructure of motor endings belonging to the stimulated .gamma. axon was examined. Myoneural junctions of trail endings supplied by static .gamma. axons to bag2 and chain fibers were smooth and folded; the deepest and most regular folding occurred on chain fibers. Terminals of p2 plates supplied to bag1 fibers by dynamic .gamma. axons had smooth myoneural junctions.