Vejsada R, Hník P, Payne R, Ujec E, Palecek J
Somatosens Res. 1985;2(3):205-22. doi: 10.3109/07367228509144564.
The response to a 5-sec stretch of the triceps muscle was studied in dorsal root filaments L5 of 72 infant rats (1-19 days old) under urethane anesthesia. More than 50% of all units in 1-day-old rats responded by repetitive firing until the end of the 5-sec stretch (slowly adapting or SA receptors), while the rest ceased to fire earlier (relatively rapidly adapting or 1/2 SA receptors), or gave an "on" response only. The number of units exhibiting an SA response increased with age and attained 80% in 5-day-old rats. By the 10th day of life, almost 90% of endings behaved as SA receptors. During development, the maximal discharge frequencies at the peak of stretch increased markedly, and their values in 18-day-old rats were comparable to those in adult rats. The phasic component of the response to stretch, although less well defined in the younger animals, was already present even in 1-day-old rats. Adaptation of the static response during maintained stretch was relatively steep in all the age groups studied. The results indicate that, in the rat, large numbers of muscle stretch receptors are capable of responding to sustained stretch as SA receptors, even at an age when their morphological and ultrastructural maturation is not yet fully accomplished.
在氨基甲酸乙酯麻醉下，研究了72只幼鼠（1 - 19日龄）L5背根细丝中肱三头肌5秒拉伸的反应。在1日龄大鼠中，超过50%的所有单位通过重复放电做出反应，直至5秒拉伸结束（慢适应或SA受体），而其余单位则更早停止放电（相对快速适应或1/2 SA受体），或仅产生“开”反应。表现出SA反应的单位数量随年龄增加，在5日龄大鼠中达到80%。到出生后第10天，几乎90%的终末表现为SA受体。在发育过程中，拉伸峰值时的最大放电频率显著增加，18日龄大鼠的值与成年大鼠相当。对拉伸反应的相位成分，尽管在幼小动物中不太明确，但在1日龄大鼠中就已存在。在所有研究的年龄组中，持续拉伸期间静态反应的适应相对陡峭。结果表明，在大鼠中，即使在其形态和超微结构成熟尚未完全完成的年龄，大量肌肉拉伸感受器也能够作为SA受体对持续拉伸做出反应。
