4 Hz EMF treated physiological solution depresses Ach-induced neuromembrane current

The effect of 4 Hz EMF treated physiological solution (PS) on acetylcholine (Ach) sensitivity of the snail neuron was studied. The 4 Hz EMF treated normal PS at room temperature (23 degrees C) has a depressing effect on Ach induced current, while in cold medium (12 degrees C) this effect disappeared. EMF treated, ouabain containing, K-free PS elevates the Ach-induced current at room temperature. It is suggested that the metabotropic effect of EMF treated PS is due to the activation of cGMP-dependent Na:Ca exchange, leading to the decrease of the number of functional active receptors in the membrane, through Na-K pump-induced cell shrinkage, and to increase the receptors affinity to Ach, as the result of decrease of intracellular Ca concentration.