K- AND TRANSMITTER-INDUCED RISES IN [CA2+](I) IN AUDITORY NEURONS OF DEVELOPING RATS()

CA(2+) TONS are thought to play important roles in processes underlyin g neuronal plasticity such as synapse stabilization. We employed the F ura-2 technique on brainstem slices of neonatal rats to measure change s in intracellular Ca2+ ([Ca2+](i)) in neurones of the lateral superio r olive (LSO) in order to analyse whether these cells have functional Ca2+ channels when synaptic maturation takes place. Rises in intracell ular Ca2+ could be induced by KCl-evoked depolarizations or by glutama te, but not by glycine or GABA. These results show that Ca2+ channels are present in developing LSO neurones and that many of them, if not a ll, belong to the voltage-sensitive type. We speculate that these chan nels play a role during ontogeny by mediating Ca2+-dependent mechanism s of synapse stabilization.