豚鼠结肠带平滑肌中镉摄取的代谢依赖性及镉的舒张作用

Metabolic dependency of cadmium uptake and the relaxant effects of cadmium in smooth muscle of guinea pig tenia coli.

作者信息

Nasu T

出版信息

Pharmacology. 1985;30(5):281-8. doi: 10.1159/000138079.

Abstract

The effects of cadmium ions on tension and lactate release under anaerobic conditions were compared with the effects of gallopamil in tenia coli. Both 0.5 mmol X 1(-1) Cd2+ and 1 X 10(-6) mol X 1(-1) gallopamil inhibited the tensions induced by high-K+ media containing a high concentration of glucose under anoxia. The increase in lactate release from the muscle tissues induced by the addition of glucose to a high-K+ medium under anoxia was inhibited by Cd2+, whereas gallopamil demonstrated only minor effects on lactate release. Following a preincubation with 0.5 mmol/l Cd2+ for 30 min under anoxia, the tension induced by high-K+ largely returned upon washing with disodium edetate (EDTA) to levels comparable to those at preincubation under normoxia. Elimination of tissue cadmium by EDTA was greater at preincubation under anoxia than when compared to normoxia. From the demonstrated kinetics of cadmium in tenia coli, it is suggested that cadmium can enter the cell in normoxic conditions. However, when cadmium is applied under anaerobic conditions, little of it seems to be able to penetrate the cell membranes.

摘要

在结肠带中，将镉离子在厌氧条件下对张力和乳酸释放的影响与加洛帕米的影响进行了比较。0.5 mmol·L⁻¹ Cd²⁺ 和 1×10⁻⁶ mol·L⁻¹ 加洛帕米均抑制了缺氧条件下含高浓度葡萄糖的高钾培养基诱导的张力。缺氧条件下向高钾培养基中添加葡萄糖诱导的肌肉组织乳酸释放增加受到 Cd²⁺ 的抑制，而加洛帕米对乳酸释放仅表现出轻微影响。在缺氧条件下用 0.5 mmol/L Cd²⁺ 预孵育 30 分钟后，用乙二胺四乙酸二钠（EDTA）洗涤后，高钾诱导的张力在很大程度上恢复到与常氧预孵育时相当的水平。与常氧相比，缺氧预孵育时 EDTA 对组织镉的清除作用更强。从结肠带中已证实的镉动力学来看，表明镉在常氧条件下可进入细胞。然而，当在厌氧条件下施加镉时，似乎很少能穿透细胞膜。