Uchida S, Kagitani F, Nakayama H, Sato A
Department of the Autonomic Nervous System, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Japan.
Neurosci Lett. 1997 Jun 13;228(3):203-6. doi: 10.1016/s0304-3940(97)00401-1.
The effect of intravenous injection of nicotine on cortical cerebral blood flow (CBF) was examined in urethane anesthetized rats. Nicotine (3-30 microg/kg) increased cortical CBF, independent of mean arterial pressure. This response was attenuated to about a half of the control one after lesioning the nucleus basalis of Meynert (NBM) bilaterally. The response was not significantly influenced after blocking the muscarinic receptors, but was abolished after blocking the nicotinic receptors in the parenchyma of the brain. It is concluded that the nicotine-induced cortical vasodilation was mediated by activation of the nicotinic receptors in the NBM and also in the cortex of the brain. The threshold dose of nicotine for increasing cortical CBF was shifted in aged rats of 23-26 months, and the nicotine-induced increase in cortical CBF was much reduced in aged rats of 32-36 months. Activation of nicotinic receptors in the brain may be of therapeutic value in aged subjects in facilitating the cholinergic neural vasodilative system.
在乌拉坦麻醉的大鼠中检测了静脉注射尼古丁对大脑皮质脑血流量（CBF）的影响。尼古丁（3 - 30微克/千克）可增加皮质CBF，且与平均动脉压无关。双侧损毁Meynert基底核（NBM）后，该反应减弱至对照反应的约一半。阻断毒蕈碱受体后，该反应未受到显著影响，但在阻断脑实质中的烟碱受体后，该反应被消除。得出的结论是，尼古丁诱导的皮质血管舒张是由NBM以及大脑皮质中的烟碱受体激活介导的。在23 - 26月龄的老年大鼠中，增加皮质CBF的尼古丁阈值剂量发生了变化，而在32 - 36月龄的老年大鼠中，尼古丁诱导的皮质CBF增加显著减少。大脑中烟碱受体的激活在促进胆碱能神经血管舒张系统方面可能对老年受试者具有治疗价值。
