Possible involvement of neurons in locus coeruleus in inhibitory effect on glossopharyngeal expiratory activity in a neonatal rat brainstem-spinal cord preparation in vitro

Tadashi Yamanishi, Hidehiko Koizumi, Masashi Komaki, Kohji Ishihama, Tadafumi Adachi, Akifumi Enomoto, Kana Takao, Seiji Iida, Mikihiko Kogo

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

In this study, we found that a certain motor branch of glossopharyngeal (IX) motor nerves stably exhibits not only inspiratory activity but also expiratory activity with pons removal in neonatal rat brainstem-spinal cord preparations in vitro. Because this finding indicates that IX expiratory activity is masked by an inhibitory mechanism operating in the pons, we sought to determine the candidate neurons that exert an inhibitory effect on IX expiratory activity. IX expiratory activity was observed when only the pons was perfused with noradrenaline (NA) or clonidine (α2 adrenergic receptor agonist), but not when NA and yohimbine (α2 adrenergic receptor antagonist) were perfused together. IX expiratory activity was also observed following the removal of the dorsal pons but not the ventral pons. The local administration of clonidine into the bilateral locus coeruleus (LC) evoked burst discharges during the expiratory phase in the IX motor rootlet. These results suggest that neurons in the LC that possess an α2 adrenergic receptor on the membrane surface exert a tonic inhibitory effect on IX expiratory activity in neonatal rat brainstem-spinal cord preparations.

Original languageEnglish
Pages (from-to)2-9
Number of pages8
JournalNeuroscience Research
Volume60
Issue number1
DOIs
Publication statusPublished - Jan 1 2008
Externally publishedYes

Keywords

  • Expiration
  • Noradrenergic
  • Pons

ASJC Scopus subject areas

  • Neuroscience(all)

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