Effect of Lanthanum on Activity of Isolated Rat's Ileum

To explore the effect and mechanisms of rare earth La on the activity of isolated rat's ileum,the investigation and the recording of the effects of LaCl3 and CaCl2,atropine and phentolamine on the activity of isolated rat's ileum were performed by the perfusion with 37°C temperature-keeping smooth muscle bath and BL-410 experimental system of biological function. The results indicated that rare earth La could significantly inhibit the activity of isolated rat's ileum. There was a competitive antagonism between La3+ and Ca2+ in the intracellular fluid of the ileum smooth muscle. Possibly La inhibited the contractile amplitude of isolated rat's ileum by weakening the excitation-contraction coupling was due to the decrease of the inflow of Ca2+ and decreased the contractile frequency by slowing the basic electrical rhythm was due to the increase of the membrane potential. Probably the inhibitory effect of La had no relation to M receptors and α receptors on the smooth muscle cells of the ileum.