Cs. Poon et al., NMDA receptor activity in utero averts respiratory depression and anomalous long-term depression in newborn mice, J NEUROSC, 20(9), 2000, pp. RC731-NIL_9
Mutant mice lacking NMDA receptor 1 subunit (NR1) showed marked depression
of respiratory and suckling activities in vivo and overexpression of synapt
ic long-term depression (LTD) in a brainstem cardiorespiratory-related regi
on (nucleus tractus solitarius) in vitro. Pharmacological blockade of NMDA
receptors in normal newborn mice mimicked the depression in suckling activi
ty but not respiratory depression in vivo or brainstem LTD in vitro. Result
s at the behavioral and cellular levels demonstrate that NMDA receptor defi
ciency during prenatal development may unleash an anomalous form of NMDA re
ceptor-independent LTD along with life-threatening respiratory depression c
onsequences in the newborn. These findings raise the specter of cardiorespi
ratory dysregulation with increased risks of morbidity and mortality in the
infant as a result of premature births or genetic or drug-induced NMDA rec
eptor antagonism during pregnancy.