Developmental changes in distribution of γ-aminobutyric acid- and glycine-immunoreactive boutons on rat trigeminal motoneurons. I. Jaw-closing motoneurons

Kyoo Paik Sang, Young Bae Jin, Euk Park Sang, Masayuki Moritani, Atsushi Yoshida, Jin Yeo Eun, Shik Choi Karp, Kuk Ahn Dong, Cheil Moon, Yoshio Shigenaga, Chul Bae Yong

Research output: Contribution to journalArticlepeer-review

Abstract

We have previously described the distribution pattern of inhibitory synapses on rat jaw-closing (JC) α- and γ-motoneurons. In the present study, we investigated developmental changes in inhibitory synapses on JC motoneurons. We performed a quantitative ultrastructural analysis of putative inhibitory synaptic boutons on JC motoneuron somata by using postembedding immunogold labeling for GABA and glycine. In total, 206, 350, and 497 boutons contacting JC motoneuron somata were analyzed at postnatal days 2 (P2), 11 (P11) and 31 (P31), respectively. The size of the somata increased significantly during postnatal development. The size distribution was bimodal at P31. Mean length of the boutons and percentage of synaptic covering also increased during postnatal development, whereas bouton density did not differ significantly among the three age groups. Synaptic boutons on the somata of JC α-motoneurons could be classified into four types: boutons immunoreactive for 1) GABA only, 2) glycine only, 3) both GABA and glycine, and 4) neither GABA nor glycine. There was no developmental change in the proportion of putative inhibitory boutons to the total number of studied boutons. However, the glycine-only boutons increased significantly (15.1% to 27.3%), and the GABA-only boutons decreased significantly (17.7% to 2.6%) during the period from P11 to P31. Our ultrastructural data indicate that the inhibitory synaptic input to JC motoneurons is developmentally regulated and that there is a postnatal switch from GABA to glycine. The postnatal changes revealed in the present study could play an important role in the maturation of the oral motor system.

Original languageEnglish (US)
Pages (from-to)779-789
Number of pages11
JournalJournal of Comparative Neurology
Volume503
Issue number6
DOIs
StatePublished - Aug 20 2007
Externally publishedYes

Keywords

  • Development
  • GABA
  • Glycine
  • HRP
  • Immunogold

ASJC Scopus subject areas

  • Neuroscience(all)

Fingerprint Dive into the research topics of 'Developmental changes in distribution of γ-aminobutyric acid- and glycine-immunoreactive boutons on rat trigeminal motoneurons. I. Jaw-closing motoneurons'. Together they form a unique fingerprint.

Cite this