Denervation-induced decreases in enzyme activity of rat superior cervical ganglia differ in vivo and in vitro

The decrease in tyrosine hydroxylase activity following denervation in vivo and subsequent culture in vitro was examined to determine the role of the preganglionic nerve in this decrease. Ganglia denervated in vivo prior to culture showed a greater decrease than ganglia maintained for the same total period in vitro, and hence denervated for the same time, suggesting factors in addition to the loss of the preganglionic nerve are involved in vivo.