The role of voltage-gated Ca2+ channels in neurite growth of cultured chromaffin cells induced by extremely low frequency (ELF) magnetic field stimulation

• Published in: Cell and tissue research Vol. 291; no. 2; p. 217
• Main Authors: Morgado-Valle, C, Verdugo-Díaz, L, García, D E, Morales-Orozco, C, Drucker-Colín, R
• Format: Journal Article
• Language: English
• Published: Germany 01.02.1998
• Subjects: 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester - pharmacology; Adrenal Medulla - cytology; Animals; Calcium - physiology; Calcium Channel Blockers - pharmacology; Calcium Channels - drug effects; Calcium Channels - physiology; Calcium Channels, L-Type; Cells, Cultured; Chromaffin Cells - drug effects; Chromaffin Cells - physiology; Electromagnetic Fields; Ion Channel Gating - physiology; Mollusk Venoms - pharmacology; Nerve Growth Factors - pharmacology; Neurites - drug effects; Neurites - ultrastructure; Nifedipine - pharmacology; Norepinephrine - metabolism; Potassium Chloride; Rats; Rats, Wistar
• ISSN: 0302-766X
• DOI: 10.1007/s004410050992

The ion Ca2+ has been shown to play an important role in a wide variety of cellular functions, one of them being related to cell differentiation in which nerve growth factor (NGF) is involved. Chromaffin cells obtained from adrenals of 2- to 3-day-old rats were cultured for 7 days. During this time, these cells were subjected to the application of either NGF or extremely low frequency magnetic fields (ELF MF). Since this induced cell differentiation toward neuronal-like cells, the mechanism by which this occurred was studied. When the L-Ca2+ channel blocker nifedipine was applied simultaneously with ELF MF, this differentiation did not take place, but it did when an N-Ca2+ channel blocker was used. In contrast, none of the Ca2+ channel blockers prevented differentiation in the presence of NGF. In addition, Bay K-8644, an L-Ca2+ channel agonist, increased both the percentage of differentiated cells and neurite length in the presence of ELF MF. This effect was much weaker in the presence of NGF. [3H]-noradrenaline release was reduced by nifedipine, suggesting an important role for L-Ca2+ channels in neurotransmitter release. Total high voltage Ca2+ currents were significantly increased in ELF MF-treated cells with NGF, but these currents in ELF MF-treated cells were more sensitive to nifedipine. Amperometric analysis of catecholamine release revealed that the KCl-induced activity of cells stimulated to differentiate by ELF MF is highly sensitive to L-type Ca2+ channel blockers. A possible mechanism to explain the way in which the application of magnetic fields can induce differentation of chromaffin cells into neuronal-like cells is proposed.