Lewandowski M H, Müller C M, Singer W
Max-Planck-Institut für Hirnforschung, Frankfurt/Main, Germany.
Exp Brain Res. 1993;96(1):1-7. doi: 10.1007/BF00230433.
Stimulation of the mesencephalic reticular formation facilitates responses in the visual cortex elicited from the optic radiation. Using intravenous administration of cholinergic antagonists we investigated in adult cats and two kittens whether this effect is mediated by cholinergic mechanisms. When administered alone the muscarinic antagonists atropine and scopolamine and the nicotinic antagonist mecamylamine failed to block reticular facilitation and sometimes even enhanced the effects of reticular stimulation. However, when administered in combination muscarinic and nicotinic antagonists eliminated or significantly reduced the facilitation. This was even true when the two antagonists were administered with a time lag of several hours. These results support the notion that reticular facilitation of cortical responses is mediated by cholinergic mechanisms and suggest that this effect is mediated either by a receptor with a mixed pharmacological property or by two independent pathways acting via nicotinic and muscarinic receptors. This hypothesis is discussed in the context of recent evidence on cholinergic transmission and earlier data on the pharmacology of reticular arousal.
刺激中脑网状结构可促进由视辐射引发的视觉皮层反应。我们通过静脉注射胆碱能拮抗剂，在成年猫和两只小猫身上研究了这种效应是否由胆碱能机制介导。单独使用时，毒蕈碱拮抗剂阿托品和东莨菪碱以及烟碱拮抗剂美加明无法阻断网状结构的易化作用，有时甚至会增强网状刺激的效果。然而，联合使用毒蕈碱和烟碱拮抗剂时，易化作用消除或显著降低。即使两种拮抗剂间隔数小时给药，情况依然如此。这些结果支持了网状结构对皮层反应的易化作用由胆碱能机制介导的观点，并表明这种效应要么由具有混合药理学特性的受体介导，要么由通过烟碱和毒蕈碱受体起作用的两条独立途径介导。我们结合近期关于胆碱能传递的证据以及早期关于网状唤醒药理学的数据，对这一假设进行了讨论。
