Effects of a time-varying magnetic field on transient increase in intracellular Ca²⁺ concentration of bovine adrenal chromaffin cells.

Abstract

We tested the effects of exposure to a switched 1.5 Tesla magnetic field on transient increase in intracellular Ca²⁺ stimulated by neurotransmitters in bovine adrenal chromaffin cells. The concentration of intracellular Ca²⁺ ([Ca²⁺]i) was increased by addition of acetylcholine (ACh) or bradykinin (BK) in chromaffin cells. These stimulator-induced increase in [Ca²⁺]i in Ca²⁺-free medium was strongly inhibited by 2 hr exposure to the magnetic field, but the exposure did not change BK-induced production of inositol 1,4,5-trisphosphate. In Ca²⁺ containing medium, the exposure delayed only the decay phase of [Ca²⁺]i after peak. Delay of the decay phase was also caused by addition of NaCN in the presence of ACh. The intracellular ATP content and oxygen consumption were influenced by the exposure in glucose-free medium. Measurement of mitochondrial membrane potential by using fluorescent probe, JC-1 (Molecular Probe), indicated depolarization of the membrane in both cells exposed to the magnetic field and added NaCN. These effects of magnetic field would be related to the eddy current. [Jpn J Physiol 55 Suppl:S77 (2005)]