Schwartz-Giblin S, Halpern M, Pfaff D W
Brain Res. 1984 May 14;299(2):247-57. doi: 10.1016/0006-8993(84)90706-6.
Following stimulation of lumbar cutaneous and high threshold muscle afferents in urethane-anesthetized ovariectomized rats, polysynaptic multi-unit responses were recorded from muscle nerves to lateral longissimus (LL) at a mean latency of 9.5 ms. These responses could be reciprocally evoked between segments with no apparent rostro-caudal asymmetry. Polysynaptic responses habituated to repeated stimulation within 0.5-1.5 min but could be evoked again after several minutes rest. In estradiol-treated rats, 60% of the 9.5 ms responses were followed by late discharges (greater than 40 ms) as compared to 24% in untreated control animals (P = 0.05). Following stimulation to the L3 and L4 motor nerves to lateral longissimus, EMG responses were recorded from overlapping fields of innervation. The conduction velocity of the fast muscle fibers was determined to be 7 m/s. The short length of most of the LL muscle fibers and the intersegmental recruitment of LL motoneurons by cutaneous afferents is compatible with the integrated action of axial muscles in the performance of lordosis behavior.
在对经乌拉坦麻醉的去卵巢大鼠的腰段皮肤和高阈值肌肉传入神经进行刺激后，从肌肉神经记录到对侧最长肌（LL）的多突触多单位反应，平均潜伏期为9.5毫秒。这些反应可在节段间相互诱发，且无明显的头尾不对称。多突触反应在0.5 - 1.5分钟内对重复刺激产生习惯化，但在休息几分钟后可再次诱发。在经雌二醇处理的大鼠中，9.5毫秒反应中有60%随后出现晚期放电（大于40毫秒），而未处理的对照动物中这一比例为24%（P = 0.05）。在对L3和L4运动神经刺激到侧最长肌后，从重叠的神经支配区域记录到肌电图反应。快速肌纤维的传导速度测定为7米/秒。大多数LL肌纤维的短长度以及皮肤传入神经对LL运动神经元的节段间募集与在脊柱前凸行为表现中轴肌的整合作用相一致。
