Billard J M, Batini C
Laboratoire de Physiologie de la Motricité, Université Pierre et Marie Curie, URA CNRS 385, CHU Pitié-Salpêtrière, Paris, France.
Neurosci Res. 1991 Jan;9(4):246-56. doi: 10.1016/0168-0102(91)90026-u.
The effects of iontophoretically applying the presumed Purkinje cell inhibitory neurotransmitters, GABA and taurine, were tested on neurons of the cerebellar nuclei in normal and in climbing-fiber-deafferented cerebella. Rats treated with 3-acetylpyridine to totally destroy the inferior olive were used for acute experiments 105-185 days after treatment. In controls, nearly all neuronal firing was dose-dependently depressed by both inhibitory amino acids. The depression in firing for both were antagonized by bicuculline and picrotoxin but not by strychnine while TAG specifically antagonized only responses to taurine. At sufficient doses, bicuculline and TAG induced disinhibitory responses (significant release of neuron discharge) in the absence of applied antagonist. In deafferented animals, the inhibitory efficacy of GABA and taurine were drastically reduced; most of the neurons failed to respond to these amino acids at the same iontophoretic parameters as for the control rats. Moreover, high doses of bicuculline and TAG did not induce any disinhibitory response (no significant increase in discharge rate) in most of the neurons tested. These results clearly demonstrate that climbing fiber deafferentation reduces postsynaptic sensitivity of the cerebellar nuclei neurons for the presumed Purkinje cell inhibitory neurotransmitters.
在正常和去攀爬纤维传入的小脑的情况下，通过离子电渗法施加推测的浦肯野细胞抑制性神经递质γ-氨基丁酸（GABA）和牛磺酸，测试其对小脑核神经元的影响。用3-乙酰吡啶处理以完全破坏下橄榄核的大鼠用于处理后105 - 185天的急性实验。在对照组中，两种抑制性氨基酸几乎都能剂量依赖性地抑制神经元放电。两种氨基酸引起的放电抑制均被荷包牡丹碱和印防己毒素拮抗，但不被士的宁拮抗，而荷包牡丹碱仅特异性拮抗对牛磺酸的反应。在没有施加拮抗剂的情况下，足够剂量的荷包牡丹碱和荷包牡丹碱会诱导去抑制反应（神经元放电显著释放）。在去传入动物中，GABA和牛磺酸的抑制效力大幅降低；在与对照大鼠相同的离子电渗参数下，大多数神经元对这些氨基酸没有反应。此外，在大多数测试的神经元中，高剂量的荷包牡丹碱和荷包牡丹碱不会诱导任何去抑制反应（放电率没有显著增加）。这些结果清楚地表明，攀爬纤维去传入会降低小脑核神经元对推测的浦肯野细胞抑制性神经递质的突触后敏感性。
