Local anaesthetics inhibit influx of calcium, sodium and potassium into rat ileum, diaphragm and human isolated saphenous vein

Abstract 1. 1. The effects of 5 different local anaesthetics, lignocaine, prilocaine, etidocaine, mepivacaine, bupivacaine, on uptake of Ca 2+ , Na + and K + were studied, using a Kone Microlyte Analyzer, into 3 different types of muscle fibres, the rat ileum, rat diaphragm and human isolated saphenous vein. 2. 2. The aim of the present experiments was to see if local anaesthetics had a calcium antagonistic activity, like that produced by calcium antagonists, e.g. verapamil. 3. 3. The results showed that local anaesthetics in moderate and high concentrations (more than 100 μM) depressed uptake of Ca 2+ , as well as the Na + and K + , although the depression of the uptake of Ca 2+ was 7 and 2 times less than those of Na + and K + . 4. 4. In low concentrations (1–10 μM), the local anaesthetics had no or little effect on Ca 2+ uptake, although they still significantly reduced Na + and K + uptake. 5. 5. It was concluded that the effect of local anaesthetics on uptake of Ca 2+ , Na + and K + into rat ileum, diaphragm and human saphenous vein, is concentration-dependent, and that only at high concentrations do they have a calcium antagonistic activity in muscle. 6. 6. Furthermore, there was no clear evidence that the effect of local anaesthetics was species-dependent, since the uptake of Ca 2+ was depressed by only about 17% more in smooth muscle than in skeletal muscle.