The effects of axotomy on the development of the rat superior cervical ganglion.

The effects of division of the postganglionic axons of the adrenergic neurones in the superior cervical ganglion of the rat were examined with regard to the total ganglionic protein content and tyrosine hydroxylase and DOPA decarboxylase activities. Axotomy before the twelfth postnatal day results in a marked atrophy of the ganglion and a reduction in the total enzyme content of the ganglion. Axotomy after postnatal day 21 results in the normal adult ganglion response with a large increase in the total protein content of the ganglion and only minor changes in the total enzyme content of the ganglion. Axotomy between the postnatal days 12 and 21 results in an intermediate response. Thus it can be concluded there is a critical period during the development of the ganglion during which the adrenergic neurones undergo a maturation governed by their contact with the peripheral target cell via axons. These results suggest a trophic role of the end organ on the adrenergic neurone.