DEVELOPMENTAL-CHANGES IN CYTOCHROME-OXIDASE HISTOCHEMISTRY IN THE MAIN AND ACCESSORY OLFACTORY BULBS OF EMBRYONIC AND NEONATAL GARTER SNAKES (THAMNOPHIS-SIRTALIS SPP)

Developmental studies examining the changes in oxidative metabolic act ivity are useful for understanding how and if the vomeronasal and olfa ctory systems respond to stimulation during embryogenesis. Garter snak es are good candidates for examining the potential functionality of th e vomeronasal system in utero. In adult garter snakes, the vomeronasal system mediates many behaviors. Neonatal garter snakes exhibit these same behaviors, and the vomeronasal system has been shown to mediate f eeding behavior in neonates. Using cytochrome oxidase histochemistry, we examined changes in the oxidative metabolic activity of main and ac cessory olfactory bulbs of embryonic and neonatal garter snakes (Thamn ophis sirtalis sirtalis and T. s. parietalis). Cytochrome oxidase stai ning is greater in the accessory olfactory bulb than in the main olfac tory bulb of embryonic garter snakes. However, neonates show no differ ences in the staining of the accessory and main olfactory bulbs, sugge sting a change in the stimulation of the main olfactory bulb after bir th. This is the first report of cytochrome oxidase histochemistry in r eptiles and in the vomeronasal system of embryonic vertebrates. (C) 19 93 Wiley-Liss, Inc.