Lupa K, Gieroba Z, Wójcik G, Niechaj A
Arch Int Physiol Biochim. 1986 Jun;94(2):91-8. doi: 10.3109/13813458609071406.
Stimulation of either A- or C-fibres in the aortic nerve inhibits sympathetic nerve discharge (SND) recorded from the renal nerve in rabbits anaesthetized with urethane. When the test inhibition of SND to stimulation of A-fibres is preceded by conditioning stimulation of the same afferents, the test response is depressed at shorter and facilitated at longer testing intervals. Facilitation of the inhibition of SND reaches 120% of control at a testing interval of 10 s. The recovery curve of inhibition of SND to activation of A-fibres has a time course of 17 s. Following conditioning activation only depression of the test inhibition of SND to stimulation of C-fibres is seen. It reaches 46% of control at an interval of 2 s and the recovery curve of inhibition of SND to stimulation of C-fibres has a time course of about 30 s. In other series of experiments the duration of the conditioning stimulation was varied while the testing intervals were fixed. At a testing interval of 2 s the reductions of the test responses are deeper and the durations of conditioning at which plateaus of depression are reached are longer with stimulation of C- than of A-fibres. Taken together with a longer recovery curve these findings suggest a more effective control of the test inhibition of SND by C-fibres. Opposite changes in the patterns of inhibition of SND to activation of either A- or C-fibres are explained by frequency-dependent post-tetanic effects of the conditioning stimulation.
刺激兔主动脉神经中的A纤维或C纤维，可抑制用氨基甲酸乙酯麻醉的兔肾神经记录到的交感神经放电（SND）。当对A纤维刺激的SND测试抑制之前先对相同传入纤维进行条件刺激时，在较短的测试间隔下测试反应受到抑制，而在较长的测试间隔下则得到易化。在10秒的测试间隔下，SND抑制的易化程度达到对照的120%。SND对A纤维激活的抑制恢复曲线的时间进程为17秒。仅在条件激活后，可见SND对C纤维刺激的测试抑制受到抑制。在2秒的间隔下，其抑制程度达到对照的46%，SND对C纤维刺激的抑制恢复曲线的时间进程约为30秒。在其他系列实验中，条件刺激的持续时间变化，而测试间隔固定。在2秒的测试间隔下，与A纤维刺激相比，C纤维刺激时测试反应的降低更明显，达到抑制平台的条件刺激持续时间更长。结合更长的恢复曲线，这些发现表明C纤维对SND测试抑制的控制更有效。SND对A纤维或C纤维激活的抑制模式的相反变化，是由条件刺激的频率依赖性强直后效应解释的。
