Inhibitory Effect Of Cadmium Research Articles

The inhibitory effect of cadmium on neuromuscular transmission in the rat

Cadmium (0.125–1 mM) was found to inhibit the isometric response of the isolated rat hemidiaphragm during indirect stimulation, but not during direct stimulation. This effect of cadmium (1 mM) was completely reversed by ethyleneglycol bis-(aminoethyl)-N,N,N′,N′-tetra-acetic acid (2 mM) or by L-cysteine (2 mM) but only partially by increased calcium. Cadmium (10 μM) significantly reduced the quantal release of transmitter in the isolated phrenic diaphragm and a concentration of 0.1 mM frequently caused a complete failure of the endplate response after 30 min. The effect of cadmium on neuromuscular transmission could not be readily reversed by washing with cadmium-free solution. Miniature endplate potential frequency and amplitude were not significantly affected by cadmium (0.1 or 0.5 mM). The results suggest that the effect of cadmium on the isolated phrenic nerve-diaphragm is due largely to inhibition of calcium function at presynaptic nerve terminals.

The inhibitory effect of cadmium on the secretory activity of the isolated perfused rat pancreas

Perfusion of the isolated rat pancreas with cadmium (Cd) (1 × 10 −3 and 5 × 10 −4 m) inhibits the insulin secretory response to glucose (300 mg/100 ml), tolbutamide (40 mg/100 ml), and potassium ions (30 mEq/liter). Cadmium inhibition of pancreatic secretory activity is immediate in onset, and not reversed by simple washout of the organ with perfusion medium. Perfusion of the inhibited organ with a combination of glucose and theophylline results in partial reversal of the inhibition. It is suspected that Cd-induced inhibition of insulin secretion may be mediated through interference with calcium uptake by the pancreatic beta cell.

Detection of Heavy Metal Toxicity by Cell Culture Method (1)

Animal test is usually employed to examine the toxicities of heavy metals. In this study, however, we used cell culture method together with the animal test to compare the results.In the cell culture, choice of cell strain is very important. In the following experiments, we used Chang's liver cells.In the animal test, metals can be classified toxicologically into two groups: the first group is harmless to the animal body (for instance, sodium, calcium, potassium and magnesium), and the second group is the body cell poison that shows acute or chronic toxicity (cadmium, mercury, chromium and arsenic).In the cell culture, sodium, calcium, potassium or magnesium is harmless to the cell growth, and inhibitory effect of cadmium, mercury, chromium or arsenic was observed.According to the foregoing results, toxicity of heavy metals in the cell culture showed the same result obtained in the animal test.It is concluded that the animal test takes a long period of time as well as greater labor and cost. We prefer the cell culture method, which provides results that are quite similar to the animal test and at the same time it can save cost, time and labor.