Kou Y R, Morton R F, Lee L Y
Department of Physiology, National Yang-Ming Medical College, Taipei, Taiwan, R.O.C.
Chin J Physiol. 1992;35(3):169-80.
The objective of this study was to determine the effect of circulated nicotine on rapidly adapting receptors (RARs) in canine lungs. Afferent activities of RARs were studied with a single fiber recording technique in 10 anesthetized, open-chest and artificially ventilated dogs. Bolus injection of nicotine (10 micrograms/kg) into either right or left atrium did not activate the RARs in the first two breaths, but it consistently evoked a mild stimulatory effect beginning approximately 3-6 breaths after the injection, accompanied by a mild increase in tracheal pressure (Pt). There was no significant difference between the receptor responses to nicotine injected via these two different routes in either the peak discharge or the latency time. By contrast, nicotine delivered by cigarette smoke directly into the airways triggered an intense burst of activity upon the very first breath of smoke delivery. Taken together, these results suggest that the sensory endings of RARs are located near the surface of airway epithelium, more easily accessible from the luminal side of the airways. The delayed stimulation of RARs following the nicotine injection was probably activated by the bronchoconstrictive effect of nicotine.
本研究的目的是确定循环中的尼古丁对犬肺中快速适应感受器（RARs）的影响。采用单纤维记录技术，在10只麻醉、开胸并人工通气的犬中研究了RARs的传入活动。向左右心房推注尼古丁（10微克/千克）在前两次呼吸中并未激活RARs，但在注射后约3 - 6次呼吸开始持续引起轻度刺激作用，同时气管压力（Pt）轻度升高。通过这两种不同途径注射尼古丁后，受体反应在峰值放电或潜伏期方面均无显著差异。相比之下，香烟烟雾中的尼古丁直接输送到气道时，在输送烟雾的第一口气时就引发了强烈的活动爆发。综上所述，这些结果表明RARs的感觉末梢位于气道上皮表面附近，更容易从气道腔侧接触到。尼古丁注射后对RARs的延迟刺激可能是由尼古丁的支气管收缩作用激活的。
