Developmental and circadian changes in Ca2+ mobilization mediated by GABAA and NMDA receptors in the suprachiasmatic nucleus.

摘要: The hypothalamic suprachiasmatic nucleus (SCN) develops as the circadian pacemaker during postnatal life. Although both GABA A and NMDA receptors are expressed in majority of SCN neurons, development their functions has not been analysed. Thus, we studied receptor-mediated Ca 2 + responses mouse slices prepared on days (P) 6-16. NMDA-induced flux was prominent maximal Mg -free conditions had no day-night variations P14-16 mice. At P6-7, extracellular reduced irrespective time whereas, after P9-10, produced a larger reduction at night than daytime. Muscimol also significantly increased developing SCN. Voltage-sensitive channel blockers inhibited muscimol-induced increase whereas tetrodotoxin effect, suggesting that stimulation postsynaptic depolarizes neurons to . Macroscopic imaging analysis demonstrated developmental preferentially nighttime group older P9-10. variation magnitude response due two cell populations, one which exhibited an other decrease muscimol. Because critical stages for exhibiting overlapped maturation firing rhythms signalling may be necessary or regulated by mature clock.