Leung F W
Research Service, Sepulveda Veterans Affairs Medical Center 91343.
Am J Physiol. 1993 Apr;264(4 Pt 2):H1087-92. doi: 10.1152/ajpheart.1993.264.4.H1087.
The hypothesis that intravenous nicotine modulates gastric spinal afferent nerve function by its ganglionic-blocking property is tested. Stimulation of the gastric spinal afferent nerves in anesthetized rats is accomplished by intragastric capsaicin irrigation. Gastric blood flow is monitored by laser-Doppler flowmetry. The increase in gastric blood flow during intragastric capsaicin irrigation is significantly reduced by 4 and 40 micrograms.kg-1.min-1 of intravenous nicotine. The inhibition appears to be specific for the spinal afferent nerves as the increase in gastric blood flow induced by electrical stimulation of the vagal afferent nerves is unaltered by these doses of intravenous nicotine. A ganglionic-blocking dose (10 mg/kg) of intraperitoneal hexamethonium also significantly attenuates the gastric vasodilatory effect of intragastric capsaicin. Intravenous nicotine (40 micrograms.kg-1.min-1) combined with intraperitoneal hexamethonium (10 mg/kg) completely abolishes the gastric vasodilatory effect of intragastric capsaicin. These data suggest that intravenous nicotine offers a specific inhibition of the gastric spinal afferent nerve-mediated hyperemia, possibly as a consequence of its ganglionic-blocking property.
对静脉注射尼古丁通过其神经节阻断特性调节胃脊髓传入神经功能这一假说进行了验证。在麻醉大鼠中，通过胃内灌注辣椒素刺激胃脊髓传入神经。采用激光多普勒血流仪监测胃血流量。静脉注射4和40微克·千克⁻¹·分钟⁻¹的尼古丁可使胃内灌注辣椒素期间胃血流量的增加显著减少。这种抑制作用似乎对脊髓传入神经具有特异性，因为这些剂量的静脉注射尼古丁不会改变由迷走神经传入神经电刺激所诱导的胃血流量增加。腹腔注射神经节阻断剂量（10毫克/千克）的六甲铵也可显著减弱胃内辣椒素的胃血管舒张作用。静脉注射尼古丁（40微克·千克⁻¹·分钟⁻¹）与腹腔注射六甲铵（10毫克/千克）联合使用可完全消除胃内辣椒素的胃血管舒张作用。这些数据表明，静脉注射尼古丁可能因其神经节阻断特性而对胃脊髓传入神经介导的充血具有特异性抑制作用。
