Dessirier J M, O'Mahony M, Sieffermann J M, Carstens E
Section of Neurobiology, Physiology and Behavior, University of California, Davis 95616, USA.
Neurosci Lett. 1998 Jan 9;240(2):65-8. doi: 10.1016/s0304-3940(97)00930-0.
Using a two-alternative forced-choice (2-AFC) discrimination test coupled with category intensity ratings, we investigated the effect of mecamylamine, an antagonist of neuronal nicotinic acetylcholine receptors (nAchRs), on oral irritation elicited by nicotine or capsaicin. Mecamylamine (0.075%) was first delivered to one side of the tongue with distilled H2O delivered to the other side. After 10 min either capsaicin (1 ppm) or nicotine (0.12%) was applied bilaterally to the tongue, and subjects were asked to choose which side yielded a stronger sensation (2-AFC) as well as to provide a rating of the irritation intensity difference between the two sides of the tongue. When nicotine was given after mecamylamine, a significant proportion of subjects chose the mecamylamine-untreated side as yielding stronger irritation. When capsaicin was given after mecamylamine, both sides of the tongue were chosen in equal numbers. These data indicate that mecamylamine reduced irritation elicited by nicotine but not capsaicin, and provide further evidence that nicotine oral irritation is mediated via a neuronal nAchR while capsaicin activates trigeminal fibers via a separate molecular receptor.
我们使用二选一强迫选择（2-AFC）辨别测试并结合类别强度评分，研究了神经元烟碱型乙酰胆碱受体（nAchRs）拮抗剂美加明对尼古丁或辣椒素引起的口腔刺激的影响。首先将美加明（0.075%）输送到舌头的一侧，另一侧输送蒸馏水。10分钟后，将辣椒素（1 ppm）或尼古丁（0.12%）双侧涂抹于舌面，要求受试者选择哪一侧产生的感觉更强（2-AFC），并对舌两侧的刺激强度差异进行评分。在美加明之后给予尼古丁时，相当一部分受试者选择未用美加明处理的一侧，认为其产生的刺激更强。在美加明之后给予辣椒素时，选择舌两侧的人数相等。这些数据表明，美加明可减轻尼古丁引起的刺激，但不能减轻辣椒素引起的刺激，并进一步证明尼古丁引起的口腔刺激是通过神经元nAchR介导的，而辣椒素则通过单独的分子受体激活三叉神经纤维。
