DEVELOPMENT OF GLYCINERGIC TRANSMISSION IN ORGANOTYPIC CULTURES FROM AUDITORY BRAIN-STEM

We investigated whether glycinergic transmission develops organotypica lly in auditory brain stem cultures. Slices of the medial nucleus of t he trapezoid body and the lateral superior olive were incubated in med ium with a raised extracellular K<SUP>+</SUP> concentration. As in viv o, glycine receptor alpha 1 subunit immunoreactivity increased and bec ame clustered on somata and proximal dendrites. Together with organoty pic expression of glycine transporter GLYT2, this indicates that molec ular components of glycinergic synapses form properly. In contrast, gl ycinergic synaptic currents did not develop as in vivo: after 7 days i n vitro they were still similar to those at the time of culture prepar ation. We suggest that for organotypic development of glycine receptor s and transporters, Ca<SUP>2+</SUP> influx due to elevated K<SUP>+</SU P> is sufficient. The development of functional synaptic transmission, however, may require patterned electrical activity. (C)<SUP></SUP> 19 98 Lippincott Williams & Wilkins.