Postnatal development of glycine receptor subunits alpha 1, alpha 2, alpha 3, and beta immunoreactivity in multiple brain stem respiratory-related nuclear groups of the rat

作者：Liu Qiuli; Wong Riley Margaret T T^*

来源：Brain Research, 2013, 1538: 1-16.

DOI：10.1016/j.brainres.2013.09.028

• Critical period
• Cuneate nucleus
• Hypoglossal nucleus
• Nucleus ambiguus
• Pre-Botzinger complex
• Ventrolateral subnucleus of solitary tract nucleus

The respiratory system is immature at birth and significant development occurs postnatally. A critical period of respiratory development occurs in rats around postnatal days. 12-13, when enhanced inhibition dominates over suppressed excitation. The mechanisms underlying the heightened inhibition are not fully understood. The present study tested our hypothesis that the inhibition is marked by a switch in glycine receptor subunits from neonatal to adult form around the critical period. An in-depth immunohistochemical and single neuron optical densitometric study was undertaken on four respiratory-related nuclear groups (the pre-Botzinger complex, nucleus ambiguus, hypoglossal nucleus, and ventrolateral subnucleus of solitary tract nucleus), and a non-respiratory cuneate nucleus in P2-21 rats. Our data revealed that in the respiratory-related nuclear groups: (1) the expressions of GlyR alpha 2 and GlyR alpha 3 were relatively high at P2, but declined after 1-11/2 weeks to their lowest levels at P21; (2) the expression of GlyR alpha 1 increased with age and reached significance at P12; and (3) the expression of G1yR beta rose from P2 to P12 followed by a slight decline until P21. No distinct increase in GlyR alpha 1 at P12 was noted in the cuneate nucleus. Thus, there is a switch in dominance of expression from neonatal GlyR alpha 2/alpha 3 to the adult GlyR alpha 1 and a heightened expression of GlyRa1 around the critical period in all respiratory-related nuclear groups, thereby supporting enhanced inhibition at that time. The rise in the expression of GlyR beta around P12 indicates that it plays an important role in forming the mature heteropentameric glycine receptors in these brain stem nuclear groups.

• 出版日期2013-11-13