Simone D A, Ngeow J Y, Whitehouse J, Becerra-Cabal L, Putterman G J, LaMotte R H
Department of Anesthesiology, Yale University School of Medicine, New Haven, Connecticut 06510.
Somatosens Res. 1987;5(2):81-92. doi: 10.3109/07367228709144620.
The magnitude and duration of itch sensation produced by intracutaneous injection of histamine were determined for humans with the procedure of magnitude estimation scaling. Thirteen subjects received a 10-microliter intracutaneous injection of histamine at doses of 0.0001, 0.001, 0.01, 0.1, 1, and 10 micrograms into the volar forearm; eight of these subjects also received a 100-microgram dose. One subject received multiple injections over several weeks to determine the reliability of the magnitude estimates of itch. Following each injection, the area of flare and duration of itch were also determined. Intracutaneous injection of histamine produced a pure sensation of itch, without pain. The magnitude of itch increased in a dose-dependent fashion. The lowest histamine dose that produced itch greater than the itch produced by vehicle was 0.01 micrograms. The greatest itch was produced by the 100-microgram dose. A power function fitted to the mean magnitude estimates had an exponent of 0.17, indicating a negatively accelerating relation between the magnitude of itch and histamine dose. The one subject who received histamine over several weeks gave fairly reproducible estimates of itch magnitude. The duration of itch and the area of flare also increased in a dose-dependent fashion. The lowest dose of histamine that produced a duration of itch longer than the itch produced by the vehicle was 0.1 microgram, while the 100-microgram dose produced the longest duration of itch. Although the area of flare increased with each increase in dose from 0.1 to 10 micrograms, the areas of flare produced by 10 and 100 micrograms of histamine did not differ. These results indicate that humans can scale the magnitude of itch produced by histamine in a dose-dependent manner. In addition, the duration of itch and the area of flare produced by histamine are dose-dependent, confirming results of previous investigators. Intracutaneous histamine is easily quantifiable and may thus be a useful stimulus in neurophysiological studies of the peripheral neural mechanisms of itch.
采用数量估计量表法，测定皮内注射组胺引起的人类瘙痒感的强度和持续时间。13名受试者在前臂掌侧接受了剂量为0.0001、0.001、0.01、0.1、1和10微克的10微升组胺皮内注射；其中8名受试者还接受了100微克剂量的注射。一名受试者在数周内接受了多次注射，以确定瘙痒强度估计的可靠性。每次注射后，还测定了红晕面积和瘙痒持续时间。皮内注射组胺产生了纯粹的瘙痒感，没有疼痛。瘙痒强度呈剂量依赖性增加。产生大于载体引起的瘙痒的最低组胺剂量为0.01微克。100微克剂量产生的瘙痒最强烈。拟合平均强度估计值的幂函数指数为0.17，表明瘙痒强度与组胺剂量之间呈负加速关系。在数周内接受组胺注射的那名受试者对瘙痒强度的估计相当可重复。瘙痒持续时间和红晕面积也呈剂量依赖性增加。产生比载体引起的瘙痒持续时间更长的最低组胺剂量为0.1微克，而100微克剂量产生的瘙痒持续时间最长。尽管从0.1到10微克，随着剂量的每次增加，红晕面积都增加，但10微克和100微克组胺产生的红晕面积没有差异。这些结果表明，人类能够以剂量依赖性方式对组胺引起的瘙痒强度进行量化。此外，组胺引起的瘙痒持续时间和红晕面积是剂量依赖性的，证实了先前研究者的结果。皮内组胺易于量化，因此可能是瘙痒外周神经机制神经生理学研究中的一种有用刺激物。
