Effects of Cu2+, Pb2+ and Zn2+ were studied on voltage-activated Na-, Ca-, and K-currents in snail neurons. It was found that: 1. In normal physiological saline Cu2+, Pb2+ and Zn2+ ions exerted complex changes on the total ionic currents; 2. All three metal ion have depressed the inward Na-currents but with different KD, moreover Pb2+ increased Na-current at low concentrations (5 μM); 3. The inward Ca-current was also reduced. The sequence of the blocking effect of metals was different: Pb>Cu>Zn, however the steady-state inactivation was influenced only by Cu2+; 4. Outward currents were decreased in all neurons by Cu2+, but the effects of Pb2+ and Zn2+ were either depression or enhancement in different indentified neurons; 5. The possibility of binding heavy metals to wide variety of membrane proteins and the observed effects on different ionic channels suggest that the metal effect is complex and cannot be taken as a specific one to a single channel type or site of location.
ASJC Scopus subject areas
- Environmental Science(all)
- Management, Monitoring, Policy and Law