Effects of axotomy on the trans-synaptic regulation of enzyme activity in adult rat superior cervical ganglia.

The effects of surgical transection of the postganglionic nerve trunk of the superior cervical ganglion on the total protein content and levels of the enzymes tyrosine hydroxylase, DOPA decarboxylase and choline acetyltransferase have been studied in the adult rat. There is a minor decrease in the total activities of these 3 enzymes accompanied by a large increase in the total protein content of the ganglion. The trans-synaptic induction of the enzyme tyrosine hydroxylase by reserpine is not affected by postganglionic axotomy. Increased activity mediated by reserpine caused no change in the total activities of either DOPA decarboxylase or choline acetyltransferase. Previously observed effects of postganglionic axotomy on preventing transmission through the ganglion are compared with these results and the possible mechanisms by which trans-synaptic induction may occur are discussed.