Svensson P, Hesslow G, Winton R
Department of Physiology and Neuroscience, Lund University, Sweden.
J Pharmacol Exp Ther. 1996 May;277(2):761-7.
Climbing fibers, which originate in the inferior olive and project to Purkinje cells and Golgi cells in the cerebral cortex, were activated at low (0.4-Hz) and high (4-Hz) frequencies by periorbital stimulation in decerebrate ferrets. Climbing fiber responses were recorded as field potentials from the c3 zone of the cerebellar surface. When periorbital stimulation was applied at high frequency, the climbing fiber responses became strongly depressed within a few seconds. It has previously been shown that this high frequency depression (HFD) of climbing fiber responses is due to a cerebellar inhibition of the inferior olive, probably via the nucleo-olivary pathway. Acute administration of ethanol had small and variable effects on the amplitude of climbing fiber responses evoked by low-frequency stimulation. In contrast, medium concentrations (0.44-2.90 g/l) of ethanol led to a marked reduction of the HFD. Low ( < 0.44 g/l) systemic concentrations had no measurable effects on the HFD, whereas high concentrations ( > 2.90 g/l) caused either an increased HFD or a nonseptic reduction in olivary excitability. Because HFD has previously been shown to involve cerebello-olivary inhibition, the possibility of an interaction between ethanol and GABA-ergic responses in the interposito-olivary pathway is discussed.
起源于下橄榄核并投射到大脑皮质浦肯野细胞和高尔基细胞的攀缘纤维，在去大脑雪貂中通过眶周刺激分别以低频率（0.4赫兹）和高频率（4赫兹）被激活。攀缘纤维反应作为小脑表面c3区的场电位进行记录。当以高频施加眶周刺激时，攀缘纤维反应在几秒钟内就会强烈抑制。先前的研究表明，攀缘纤维反应的这种高频抑制（HFD）是由于小脑对下橄榄核的抑制作用，可能是通过核橄榄体通路实现的。急性给予乙醇对低频刺激诱发的攀缘纤维反应幅度影响较小且变化不定。相比之下，中等浓度（0.44-2.90克/升）的乙醇会导致高频抑制明显降低。低浓度（<0.44克/升）的全身浓度对高频抑制没有可测量的影响，而高浓度（>2.90克/升）则会导致高频抑制增加或橄榄体兴奋性非特异性降低。由于先前已表明高频抑制涉及小脑橄榄体抑制，因此讨论了乙醇与中介核橄榄体通路中γ-氨基丁酸能反应之间相互作用的可能性。
