Effects of Cd++ on short-circuit current across epithelial membranes

Abstract

Summary. Cadmium ion (Cd ++) significantly increased potential difference (PD) and short-circuit current (SCC) across isolated frog skin when added to the outside Ringer's solution at 10 -~, 10 -3 and 5x 10-3M concentration. Resistance was reduced by 10-~ Cd ++ but not significantly changed by the higher concentrations.

Effects of Cadmium on the Active Transport of Sodium by the Abdominal Skin of a Bullfrog (Rana Catesbeiana)

“…Ca has been known as a competitive antagonist with Cd in the contractility of the cardiac muscle (HAYASHI and HoRIUCHI,1971).Ca has been also shown to counteract with Cd in the acetylcholine releasing mechanism from the peripheral end of vagal nerve (HAYASHI and TAKAYAMA,1977).In the present study with frog skin,we observed approximately 35%increase in SCC,10%decrease in RM in Ca-free EDTA Ringer's solution,while application of 2mm Ca brought about 20%decrease in SCC.These results closely resemble those of HILLYARD and GONICK(1976)and CURRAN and GILL(1962).From the above results,however,we could not conclude at the present moment that Cd and Ca counteract with each other though these two ionic species have an opposite effects on SCC and RM.…”

“…Frog skin has long been regarded as an excellent material for the study of active transport of Na because of the easiness of flux measurements and electrical studies (UssING,1949).The effects of various metal ions,such as Ca (CURRAN and GILL,1962), Cu(ZADUNAISKY et al,1963;FERREIRA,1970),La (MARTINEZ-PALOMO et al,1971)and Cd (STYMANS and BORGHGRAEF,1969;HILLYARD and GONICK, 1976),have been studied in the frog skin to elucidate the mechanism of the active transport on Na.We are especially interested in the effect of Cd, because it has been known to be antagonistic to calcium which plays some important roles in regulation of normal physiological functions in various preparations such as contraction of cardiac muscle and neurotransmitter release from autonomic nerve endings (HAYASHI and HORIUCHI,1971;HAYASHI and TAKAYAMA, 1977).The active transport by frog skin was decreased by Ca (CURRAN and GILL,1962),therefore,we examined Cd effects on the frog skin in order to find out whether Cd might exert an effect opposite to Ca,i.e.,does it increase the Na active transport or not.…”

Acute and chronic effects of cadmium on blood homeostasis of an estuarine crab, Chasmagnathus granulata, and the modifying effect of salinity

“…Therefore, the primary active mechanism for sodium uptake (i.e., Na + /K + -ATPase) seems to function normally in cadmium-exposed crabs. However, we cannot rule out a possible effect of cadmium on apical transporters and channels for sodium; in this respect, it has been reported that cadmium stimulates sodium absorption across the amphibian skin at the level of the apical membrane (32).…”

Effect of FeCl3 on ion transport in isolated frog skin

“…The effect of multivalent ions and transition metal ions is more difficult to assess largely because interactions with other molecules may also involve complex ion formation including the stoichiometric binding of water [10,14]. There have been several investigations of the effects of heavy metals such as La 3+ [13,17,30], Mn 2+ [15] and Cd 2+ [18] on transport properties across the skin. These studies each included measurements of Io, but in some cases the current carriers were not identified directly using tracer flux determinations.…”