Koppert W, Reeh P W, Handwerker H O
Institut für Physiologie und Biokybernetik, University of Erlangen/Nürnberg, FRG.
Neurosci Lett. 1993 Apr 2;152(1-2):117-20. doi: 10.1016/0304-3940(93)90497-9.
The effect of a conditioning bradykinin application on histamine induced excitation of cutaneous nociceptors and on histamine induced sensations of volunteers was studied. Using an in vitro skin nerve preparation, unmyelinated polymodal nociceptor units of rats (n = 11) were tested by bathing their receptive fields from the corium side with 10(-5) M solutions of bradykinin and histamine. Following bradykinin superfusion the histamine induced discharges were enhanced, and previously unresponsive units were excited by histamine. Corresponding psychophysical experiments were carried out in 13 healthy volunteers. Histamine iontophoresis (30 mC) induced predominantly itching sensations after an intracutaneous control injection of physiological saline. However, following bradykinin injections (100 microliters of a 10(-7) M solution) histamine induced little itch but rather a burning sensation lasting 1-2 min. Itching remained suppressed even after the burning sensations had subsided. These data support a hypothesis according to which itching is mediated by a sub-population of polymodal nociceptor units, and pain is induced whenever a larger nociceptor population is recruited. In the CNS itch processing is either occluded (masked) by pain processing, or suppressed by inhibitory processes.
研究了预处理缓激肽对组胺诱导的皮肤伤害感受器兴奋以及对志愿者组胺诱导感觉的影响。使用体外皮肤神经制备方法，通过从真皮侧用10(-5)M的缓激肽和组胺溶液冲洗大鼠（n = 11）的无髓多模式伤害感受器单位的感受野来进行测试。缓激肽灌注后，组胺诱导的放电增强，并且先前无反应的单位被组胺兴奋。在13名健康志愿者中进行了相应的心理物理学实验。皮内注射生理盐水作为对照后，组胺离子导入（30 mC）主要引起瘙痒感。然而，注射缓激肽（100微升10(-7)M溶液）后，组胺引起的瘙痒很少，而是持续1 - 2分钟的灼痛。即使灼痛消退后，瘙痒仍被抑制。这些数据支持了一种假设，即瘙痒由多模式伤害感受器单位的一个亚群介导，并且每当招募到更大的伤害感受器群体时就会诱发疼痛。在中枢神经系统中，瘙痒处理要么被疼痛处理阻断（掩盖），要么被抑制过程抑制。
