HISTOCHEMICAL DETECTION OF AGE-RELATED AND INJURY-RELATED CHANGES IN SIGNAL-TRANSDUCTION IN THE SUPERIOR CERVICAL-GANGLION

The superior cervical ganglion (SCG) is thought to be a good model for correlation studies of morphology, function and metabolism of neurons . The SCG has a relatively simple organization, it can be easily manip ulated in situ, and it maintains synaptic transmission and a high meta bolic rate during in vitro incubations. The histology and structure of SCG neurons have been characterized in detail, and physiologic stimul i, injury and aging have all been found to induce changes in the SCG m orphology. During the last decade, research in the field of signal tra nsduction has greatly expanded. Several signal transduction pathways h ave been identified that participate in the regulation of neurotransmi tter synthesis, gene expression, neuronal excitability and growth fact or responses of sympathetic neurons. Pie have been interested in using the SCG to study some of the second and third messengers involved in converting external stimuli received by sympathetic neurons into cellu lar short- and long-term events. Using immunohistochemistry, we have i nvestigated protein kinase C-subtypes and the immediate early gene pro duct Fos in the SCG, and characterized some of the changes induced by injury and aging in these messenger molecules. We will review the resu lts and discuss the advantages and disadvantages of using histological methods in the study of signal transduction in sympathetic neurons. ( C) 1996 Wiley-Liss, Inc.