Neurochemical development of brain stem nuclei involved in the control of respiration.
The first two postnatal weeks are the most dynamic in the development of brain stem respiratory nuclei in the rat, the primary model for this review. Several neurochemicals (glutamate, glycine receptors, choline acetyltransferase, serotonin, norepinephrine, and thyrotropin-releasing hormone) increase expression with age, while others (GABA, serotonin receptor 1A, substance P, neurokinin 1 receptor, and somatostatin) decrease their expression. Surprisingly, a dramatic shift occurs at postnatal day (P) 12 in the rat. Excitatory neurotransmitter glutamate and its NMDA receptors fall precipitously, whereas inhibitory neurotransmitter GABA, GABA(B), and glycine receptors rise sharply. A concomitant drop in cytochrome oxidase activity occurs in respiratory neurons. Several receptor types undergo subunit switches during development. Notably, GABA(A) receptors switch prevalence from alpha3- to an alpha1-dominant form at P12 in the pre-Bötzinger complex of the rat. The transient dominance of inhibitory over excitatory neurotransmission around P12 may render the respiratory system sensitive to failure when stressed. Relating these neurochemical changes to physiological responses in animals and to sudden infant death syndrome in humans will be a challenge for future research.
Wong-Riley
Margaret T T
MT
Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA. mwr@mcw.edu
Liu
Qiuli
Q
D000818:Animals; D001933:Brain Stem / Q000033:anatomy & histology / Q000254:growth & development*; D006801:Humans; D018377:Neurotransmitter Agents / Q000378:metabolism*; D012143:Respiratory Physiological Phenomena
D018377:Neurotransmitter Agents