Developmental Changes in Dorsal Subcoeruleus Nucleus

407 Glutamatergic Transmission in the SubCD—Simon et al the SubCD.8,9 The SubCD contains glutamatergic, and perhaps GABAergic, neurons.10 Efferents of the SubCD project to a number of areas, including the medulla (involved in generating muscle atonia), the thalamus (involved in the generation of cortical oscillations and PGO waves), and the hippocampus (involved in learning and memory).3 Considering the importance of the SubCD in generating REM sleep,3,4,6,11,12 perhaps developmental changes in excitation of the SubCD could underlie the developmental decrease in REM sleep in that occurs humans from birth until the end of puberty and in the rat from postnatal days 10 to 30.13,14 Cholinergic neurotransmission has been thoroughly tested in the SubCD in vitro.15,16 However, while glutamatergic neurotransmission has been found to be important for the generation of REM sleep,4,10 the role of glutamatergic neurotransmission in the SubCD has yet to be tested in vitro. We tested the hypothesis that glutamatergic neurotransmission is important in the excitation of SubCD neurons, and developmental changes in glutamatergic neurotransmission in this nucleus may underlie the developmental decrease in REM sleep in the rat.