γ-氨基丁酸、印防己毒素和荷包牡丹碱对培养的小脑浦肯野细胞自发生物电活动的影响。

The effects of GABA, Picrotoxin and bicuculline on the spontaneous bioelectric activity of cultured cerebellar Purkinje cells.

作者信息

Gähwiler B H

出版信息

Brain Res. 1975 Nov 28;99(1):85-95. doi: 10.1016/0006-8993(75)90610-1.

Abstract

Addition of GABA to the bathing medium in concentrations of 10(-6) to 10(-5) M abolished the spontaneous bioelectric activity of rat Purkinje cells in vitro. Lower concentrations of GABA (less than or equal to 10(-6) M) influenced the firing pattern of spontaneous discharges in such a way that the relative number of long interspike intervals increased. The inhibitory effect of GABA was reversible; the cells resumed normal activity after being transferred to a normal balanced salt solution. The action of GABA was antagonized by bicuculline and picrotoxin, whereas strychnine was unable to overcome the inhibition induced by GABA. Both bicuculline (10(-10) to 10(-6) M) and picrotoxin (10(-7) to 10(-4) M) exerted an excitatory effect on cultured Purkinje cells when added to the medium. This excitatory action suggests the existence of inhibitory synapses in cultures of rat cerebellum in which endogenous GABA is used as a transmitter. The ratio between the dose of picrotoxin and that of bicuculline necessary to produce maximal excitation was in the order of 10(3). Both substances showed an inhibitory action at high concentrations.

摘要

在体外培养环境中加入浓度为10⁻⁶至10⁻⁵M的γ-氨基丁酸（GABA）可消除大鼠浦肯野细胞的自发生物电活动。较低浓度的GABA（小于或等于10⁻⁶M）会影响自发放电的放电模式，使长峰间期的相对数量增加。GABA的抑制作用是可逆的；将细胞转移到正常平衡盐溶液后，细胞恢复正常活动。GABA的作用可被荷包牡丹碱和印防己毒素拮抗，而士的宁无法克服GABA诱导的抑制作用。当向培养基中添加荷包牡丹碱（10⁻¹⁰至10⁻⁶M）和印防己毒素（10⁻⁷至10⁻⁴M）时，它们对培养的浦肯野细胞均有兴奋作用。这种兴奋作用表明在大鼠小脑培养物中存在抑制性突触，其中内源性GABA用作神经递质。产生最大兴奋所需的印防己毒素剂量与荷包牡丹碱剂量之比约为10³。两种物质在高浓度时均表现出抑制作用。