寄居蟹神经肌肉接头处突触前和突触后抑制性受体的一些特征。
Some characteristics of pre- and post-synaptic inhibitory receptors at the hermit crab neuromuscular junction.
作者信息
Balashov N, Earl J, Large W A
出版信息
Br J Pharmacol. 1975 Jul;54(3):383-8. doi: 10.1111/j.1476-5381.1975.tb07579.x.
1 The effects of gamma-aminobutyric acid (GABA), beta-guanidinopropionic acid (betaGP) and picrotoxin on the pre- and post-synaptic receptors of the hermit crab neuromuscular junction were studied quantitatively usine electrophysiological techniques. Reductions in excitatory junction potential (e.j.p.) amplitude and membrane resistance were measured simultaneously from the same cells. 2 The pre- and post-synaptic receptors were activated by the same order of concentration of GABA, whereas betaGP stimulated the pre-synaptic receptors at a concentration ten times lower than was required to affect the post-synaptic membrane. 3 Picrotoxin appeared to antagonize the pre-synaptic action of betaGP in a competitive manner. The affinity constants (+/- s.e. mean) for picrotoxin 5 times 10(-6)M and 2 times 10(-4)M were 6.80(+/-0.46) times 10(5)M-1 and 6.42(+/-1.8) times 10(5)M-1 respectively. 4 The effect of GABA on e.j.p. amplitude also appeared to be antagonized competitively by picrotoxin whereas the post-synaptic effect was antagonized in a non-competitive manner. 5 Possible differences in the nature of the pre- and post-synaptic receptors are discussed.
运用电生理技术，定量研究了γ-氨基丁酸（GABA）、β-胍基丙酸（βGP）和印防己毒素对寄居蟹神经肌肉接头突触前和突触后受体的影响。从同一细胞中同时测量兴奋性接头电位（e.j.p.）幅度和膜电阻的降低情况。
GABA以相同的浓度顺序激活突触前和突触后受体，而βGP刺激突触前受体的浓度比影响突触后膜所需的浓度低10倍。
印防己毒素似乎以竞争性方式拮抗βGP的突触前作用。印防己毒素5×10⁻⁶M和2×10⁻⁴M的亲和常数（±标准误平均值）分别为6.80（±0.46）×10⁵M⁻¹和6.42（±1.8）×10⁵M⁻¹。
印防己毒素似乎以竞争性方式拮抗GABA对e.j.p.幅度的作用，而对突触后作用的拮抗方式为非竞争性。
讨论了突触前和突触后受体性质可能存在的差异。
Zotero 插件