ABSTRACT
The ontogeny of ligand binding to N-methyl-D-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate (KA) receptors and to the high affinity, sodium-dependent D-aspartate binding site in prenatal and postnatal ovine brains was studied using quantitative in vitro autoradiography. In general, the binding density for each of the excitatory amino acid receptors peaked during late prenatal and early postnatal development. In contrast, binding density for D-aspartate remained low during late prenatal and early postnatal development and peaked in the adult. These data suggest that an excess number of excitatory amino acid receptors and/or a relative deficiency of transporters may make the immature brain more vulnerable to the pathologic effects of glutamate and other related excitatory amino acids.
Subject(s)
Aging/metabolism , Animals, Newborn/metabolism , Aspartic Acid/metabolism , Brain/embryology , Brain/metabolism , Receptors, Glutamate/metabolism , Animals , Animals, Newborn/growth & development , Autoradiography , Binding Sites , Embryonic and Fetal Development/physiology , Fetus/metabolism , Fetus/physiology , Glutamic Acid/metabolism , Kainic Acid/metabolism , N-Methylaspartate/metabolism , Sheep/embryology , alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid/metabolismABSTRACT
OBJECTIVE: We hypothesized that during a simulated neonatal resuscitation, heart rate determination with the Neonatal Resuscitation Program's (NRP) 6-second method is difficult and results in inaccuracies. We tried to determine whether a simple electronic timing device improves accuracy of heart rate determination. METHODS: One-hundred fourteen clinicians determined four heart rates under conditions simulating a resuscitation by three different methods: their own method, NRP's 6-second method, and an electronic timing device method. Responses were scored as correct if they would have resulted in the same intervention as called for by NRP criteria for each specific heart rate tested. RESULTS: Of 1368 total responses, 267 (19.5%) were incorrect, which could have led to either an inappropriate intervention or lack of an appropriate intervention. The electronic timing device resulted in fewer errors (4%) compared with when clinicians used their own methods (32%) and the NRP's 6-second method (22%). CONCLUSION: The use of a simple electronic timing device improves accuracy of heart rate determination compared with the NRP's 6-second method or when clinicians use their own methods.
