Excitatory-inhibitory imbalance in hypoglossal neurons during the critical period of postnatal development in the rat. J Physiol 2011 Apr 15;589(Pt 8):1991-2006
Date
04/14/2011Pubmed ID
21486774Pubmed Central ID
PMC3090599DOI
10.1113/jphysiol.2010.198945Scopus ID
2-s2.0-79954471811 (requires institutional sign-in at Scopus site) 45 CitationsAbstract
Hypoglossal motoneurons (HMs) innervate tongue muscles and are critical in maintaining patency of the upper airway during respiration. Abnormalities in HMs have been implicated in sudden infant death syndrome (SIDS) and obstructive sleep apnoea. Previously, we found a critical period in respiratory network development in rats around postnatal day (P) 12-13, when abrupt neurochemical, metabolic and physiological changes occurred. To test our hypothesis that an imbalance between inhibitory and excitatory synaptic transmission exists during the critical period, whole-cell patch-clamp recordings of HMs were done in brainstem slices of rats daily from P0 to P16. The results indicated that: (1) the amplitude and charge transfer of miniature excitatory postsynaptic currents (mEPSCs) were significantly reduced at P12-13; (2) the amplitude, mean frequency and charge transfer of miniature inhibitory postsynaptic currents (mIPSCs) were significantly increased at P12-13; (3) the kinetics (rise time and decay time) of both mEPSCs and mIPSCs accelerated with age; (4) the amplitude and frequency of spontaneous EPSCs were significantly reduced at P12-13, whereas those of spontaneous IPSCs were significantly increased at P12-13; and (5) both glycine and GABA contributed to mIPSCs. However, GABAergic currents fluctuated within a narrow range during the first three postnatal weeks, whereas glycinergic ones exhibited age-dependent changes comparable to those of total mIPSCs, indicating a reversal in dominance from GABA to glycine with development. Thus, our results provide strong electrophysiological evidence for an excitatory-inhibitory imbalance in HMs during the critical period of postnatal development in rats that may have significant implications for SIDS.
Author List
Gao XP, Liu QS, Liu Q, Wong-Riley MTAuthor
Qing-song Liu PhD Professor in the Pharmacology and Toxicology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Age FactorsAging
Analysis of Variance
Animals
Animals, Newborn
Brain Stem
Electric Stimulation
Excitatory Postsynaptic Potentials
Glycine
Humans
Hypoglossal Nerve
In Vitro Techniques
Infant
Inhibitory Postsynaptic Potentials
Kinetics
Motor Neurons
Neural Inhibition
Neurotransmitter Agents
Patch-Clamp Techniques
Rats
Rats, Sprague-Dawley
Sudden Infant Death
Synaptic Transmission
Tongue
gamma-Aminobutyric Acid