Poage R E, Zengel J E
Department of Veterans Affairs Medical Center, Gainesville, Florida.
Synapse. 1993 May;14(1):81-9. doi: 10.1002/syn.890140111.
We have characterized the kinetic and pharmacological properties of stimulation-induced increases of synaptic efficacy in the embryonic chick ciliary ganglion. We found what appear to be four components of increased ganglionic efficacy with average time constants of decay of about 60 msec, 400 msec, 30 sec, and 200 sec. These time constants are similar to the those describing the decay of the four components of stimulation-induced increases in neurotransmitter release characterized at other synapses. These components have been termed first and second components of facilitation, augmentation, and potentiation. We found that the addition of small amounts of Ba2+ to the low Ca2+ bathing solution led to an increase in the magnitude of the augmentation-like component, whereas Sr2+ enhanced the magnitude and time course of the component resembling the second component of facilitation. These effects of Ba2+ and Sr2+ are similar to the effects of these same divalent cations on augmentation and the second component of facilitation, respectively, at the frog neuromuscular junction and rabbit superior cervical ganglion. Based on these similar kinetic and pharmacological properties, we conclude that the four components of stimulation-induced increases in release that have been described in other synaptic preparations also appear to be present in the chick ciliary ganglion.
我们已经对胚胎期鸡睫状神经节中刺激诱导的突触效能增加的动力学和药理学特性进行了表征。我们发现神经节效能增加似乎有四个成分，其平均衰减时间常数分别约为60毫秒、400毫秒、30秒和200秒。这些时间常数与描述其他突触处刺激诱导的神经递质释放增加的四个成分衰减的时间常数相似。这些成分被称为易化、增强和强直增强的第一和第二成分。我们发现，在低钙的浴液中添加少量的Ba2+会导致类似增强成分的幅度增加，而Sr2+则增强了类似于易化第二成分的成分的幅度和时程。Ba2+和Sr2+的这些作用分别与相同二价阳离子对青蛙神经肌肉接头和兔颈上神经节的增强和易化第二成分的作用相似。基于这些相似的动力学和药理学特性，我们得出结论，在其他突触制剂中描述的刺激诱导释放增加的四个成分在鸡睫状神经节中似乎也存在。
