Regulation of intracellular calcium and preprotachykinin neurotransmitter precursor gene expression by patterned electrical stimulation in rat sympathetic neurons.

Experiments were performed to test several predictions of the hypothesis that activity pattern-dependent changes in intracellular free calcium concentration ([Ca2+]i) might play a role in the translation of altered patterns of neuronal activity into changes in neurotransmitter gene expression. It was shown that (1) the Ca2+ channel blocker cadmium prevented depolarization-induced preprotachykinin-I (PPT-I) gene repression in rat sympathetic neurons; (2) the magnitudes of transient rises in [Ca2+]i were dependent upon the pattern in which a fixed number of depolarizing stimuli were delivered; and (3) stimulation at 10 Hz for 24 h did not repress PPT-I mRNA, while the same number of pulses delivered in 0.2 s bursts of 50 Hz caused a highly significant reduction to 30 +/- 2.5% of control levels.