Calcium currents of embryonic and adult neurons in serum-free culture

Calcium channels affect many neuronal functions, including membrane electrical excitability, synaptic transmission, cellular homeostasis, gene transcription, growth, and development. We used recently developed methods for serum-free culture of adult and embryonic rat neurons to study the development of voltage-sensitive calcium currents. We compared characteristics of voltage-sensitive calcium currents in neurons taken from juvenile adult (2-4 months of age) and embryonic (day 18) rats. Mean total calcium currents were 67% larger in embryonic compared to adult neurons. At both ages, calcium currents contained only high-voltage-activated components, and tacked low-voltage-activated components. High-voltage-activated currents were significantly greater in embryonic than in adult neurons, but the voltage-sensitivity was similar. Our adult cultures, but not embryonic cultures, contain basic fibroblast growth factor (FGF2), which enhances survival. We tested the effect of FGF2 and found that growth in its presence caused increased calcium currents in both embryonic and adult neurons. We conclude that in neurons cultured in serum-free medium, neuronal development from embryonic to juvenile adult ages is associated with a significant reduction in voltage-sensitive calcium currents. (C) 1999 Elsevier Science Inc.