Hamilton T C, Osborn D
J Cell Physiol. 1977 Jun;91(3):403-8. doi: 10.1002/jcp.1040910310.
Measurements made on contraction latencies in Spirostomun suggest that mechanical stimulation causes contractions to be initiated by the release of small amounts of calcium from a store tightly coupled to the contractile apparatus. Contraction to electrical stimulation appears to result from the gross electrophoretic mobilization of large amounts of calcium from a loosely coupled store. Contraction latencies to mechanical stimulation were three milliseconds and were independent of stimulus strength, previous stimulation, and contraction probability. For 0.5-millisecond biphasic electrical stimulation the contraction latencies varied widely. Latencies to initial contractions were dependent on stimulus strength: from 1.0 milliseconds for a stimulus that caused a 100% probability of contraction to 2.0 milliseconds for a stimulus that caused a 10% probability of contraction. Latencies of contraction to electrical stimulation were also dependent upon previous stimulation, lengthening to over 300 milliseconds after ten minutes of stimulation. Initial contraction latencies were not affected by previous stimulation to the other (electrical or mechanical) stimulus modality. Repeated electrical stimulation also reduced the animal's resting length and slowed the rate of post contraction re-extension, whereas mechanical stimulation did not have these effects.
对旋口虫收缩潜伏期的测量表明，机械刺激会促使收缩由紧密连接收缩装置的钙库中释放少量钙引发。电刺激引发的收缩似乎来源于大量钙从连接松散的钙库中的总体电泳动员。机械刺激的收缩潜伏期为3毫秒，且与刺激强度、先前刺激及收缩概率无关。对于0.5毫秒的双相电刺激，收缩潜伏期变化很大。初始收缩潜伏期取决于刺激强度：引发100%收缩概率的刺激潜伏期为1.0毫秒，引发10%收缩概率的刺激潜伏期为2.0毫秒。电刺激的收缩潜伏期还取决于先前刺激，在刺激十分钟后延长至300多毫秒。初始收缩潜伏期不受先前对另一种（电或机械）刺激方式的刺激影响。重复电刺激还会缩短动物的静息长度并减缓收缩后再伸展的速率，而机械刺激则没有这些影响。
