Nilsson H, Ljung B, Sjöblom N, Wallin B G
Acta Physiol Scand. 1985 Mar;123(3):303-9. doi: 10.1111/j.1748-1716.1985.tb07592.x.
Contractile responses to electrical field stimulation of excised small mesenteric arteries and veins of the rat were compared when stimuli were delivered in irregular bursts or at regular intervals. Spontaneously occurring skin vasoconstrictor impulses in a few-unit median nerve recording in man were stored on tape and used to trigger a stimulator. Two irregular stimulation sequences at average frequencies of 1.6 and 1.8 Hz, respectively, were used. In the arteries, average contractile responses were significantly greater at an irregular than at an even stimulation frequency, but in the veins, similar degrees of contraction were obtained with the two modes of stimulation. The frequency-response relationships to continuous regular stimulation showed the artery to respond less than the vein at low frequencies. This apparently explains the differences in behaviour between the vessels to irregular stimulation. The results show that not only the number of impulses, but also their pattern of occurrence, may influence the degree of vasoconstriction. Thus, the normal irregular sympathetic discharge pattern in itself has a bearing on the physiology of neuro-effector control mechanisms.
当以不规则脉冲串或固定间隔施加刺激时，比较了电场刺激大鼠离体小肠系膜动脉和静脉所引起的收缩反应。在人体少数单位的正中神经记录中，自发出现的皮肤血管收缩冲动被记录在磁带上，并用于触发刺激器。使用了两个平均频率分别为1.6Hz和1.8Hz的不规则刺激序列。在动脉中，不规则刺激频率下的平均收缩反应明显大于均匀刺激频率下的反应，但在静脉中，两种刺激模式下获得的收缩程度相似。对连续规则刺激的频率-反应关系表明，在低频时动脉的反应小于静脉。这显然解释了血管对不规则刺激的行为差异。结果表明，不仅冲动的数量，而且其出现的模式，都可能影响血管收缩的程度。因此，正常的不规则交感神经放电模式本身与神经效应器控制机制的生理学有关。
