THE USE OF IN-VITRO PREPARATIONS OF THE ISOLATED AMPHIBIAN CENTRAL-NERVOUS-SYSTEM IN NEUROANATOMY AND ELECTROPHYSIOLOGY

In the present study an isolated preparation of the complete anuran ce ntral nervous system (CNS) is described which can be kept alive for se veral days and allows tracing, immunohistochemical and electrophysiolo gical studies. A simple perfusion chamber is being used in which the i solated CNS preparation is superfused with oxygenated Ringer. The use of an isolated CNS has many advantages including: (1) virtually all ar eas are easily accessible at the same time without having the problem of blood vessels that hinder access; (2) large lesions and massive tra cer applications are possible without survival problems of the animal, and tracers will not be translocated by blood circulation; (3) since pulsations caused by the pressure chan es of blood circulation do not occur, intracellular recordings are comparatively easy and stable; and (4) this approach offers the possibility of working on the same brain for several days by storing the preparation in a refrigerator overnig ht at low temperatures, thus allowing extensive utilization of a singl e preparation and reduction in the number of experimental animals requ ired, Some applications to the anuran auditory system illustrate that the isolated anuran CNS is well-suited for a variety of neuroanatomica l and physiological techniques.