Brackley P, Goodnow R, Nakanishi K, Sudan H L, Usherwood P N
Department of Zoology, University of Nottingham, U.K.
Neurosci Lett. 1990 Jun 22;114(1):51-6. doi: 10.1016/0304-3940(90)90427-b.
The effects of spermine and a synthetic analogue (PhTX-343) of the polyamine amide toxin, delta-philanthotoxin, on the responses of Xenopus oocytes to application of amino acids were examined using voltage clamp. The oocytes were injected with either total rat brain RNA or chick cerebrum, poly(A+)RNA. The responses to N-methyl-D-aspartate and L-kainate were potentiated by low concentrations (10(-11)-10(-7) M) of PhTX-343 and by 10(-5)-10(-4) M spermine. There was variability between oocytes in terms of their responsiveness to these compounds and recovery from their effects was slow and often incomplete. Prolonged or repeated applications of PhTX-343 and spermine eventually resulted in inhibition. Higher concentrations of these compounds always inhibited the responses to acidic amino acids. Low concentrations of PhTX-343 and spermine also potentiated the responses to nicotine and gamma-aminobutyric acid. These results are discussed in terms of the postulated polyamine binding site on the N-methyl-D-aspartate receptor.
使用电压钳研究了精胺和多胺酰胺毒素δ- philanthotoxin的合成类似物（PhTX - 343）对非洲爪蟾卵母细胞对氨基酸应用反应的影响。卵母细胞注射了大鼠全脑RNA或鸡大脑的聚腺苷酸RNA（poly(A+)RNA）。低浓度（10(-11)-10(-7) M）的PhTX - 343和10(-5)-10(-4) M的精胺增强了对N - 甲基 - D - 天冬氨酸和L - 海藻酸的反应。卵母细胞对这些化合物的反应存在差异，且从其作用中恢复缓慢且往往不完全。长时间或重复应用PhTX - 343和精胺最终导致抑制。这些化合物的较高浓度总是抑制对酸性氨基酸的反应。低浓度的PhTX - 343和精胺也增强了对尼古丁和γ-氨基丁酸的反应。根据N - 甲基 - D - 天冬氨酸受体上假定的多胺结合位点对这些结果进行了讨论。
