de la Garza R, McGuire T J, Freedman R, Hoffer B J
University of Colorado Health Sciences Center, Department of Pharmacology, Denver 80262.
Neuroscience. 1987 Dec;23(3):887-91. doi: 10.1016/0306-4522(87)90165-5.
Nicotine, locally applied to identified neurons in the rat cerebellar cortex, excites inhibitory interneurons, but depresses the discharge of Purkinje cells. Alpha-bungarotoxin blocked the excitatory actions of nicotine on the inhibitory interneurons. The antagonism of nicotine excitatory actions is largely irreversible and also insurmountable with higher doses of nicotine. The antagonism by alpha-bungarotoxin is, in addition, selective since there is no blockade of the inhibitory actions of nicotine on Purkinje neurons. The present data suggest that the excitatory actions of nicotine on inhibitory interneurons are mediated by neuromuscular-type nicotinic receptors in the cerebellum. Moreover, the present data also supports the hypothesis of multiple nicotinic sites of action in mammalian brain.
将尼古丁局部应用于大鼠小脑皮质中已确定的神经元时，它会兴奋抑制性中间神经元，但抑制浦肯野细胞的放电。α-银环蛇毒素阻断了尼古丁对抑制性中间神经元的兴奋作用。尼古丁兴奋作用的拮抗作用在很大程度上是不可逆的，而且高剂量的尼古丁也无法克服这种拮抗作用。此外，α-银环蛇毒素的拮抗作用具有选择性，因为它不会阻断尼古丁对浦肯野神经元的抑制作用。目前的数据表明，尼古丁对抑制性中间神经元的兴奋作用是由小脑中神经肌肉型烟碱受体介导的。此外，目前的数据也支持哺乳动物脑中存在多个烟碱作用位点的假说。
