Endogenous serotonin contributes to a developmental decrease in long-term potentiation in the rat visual cortex

Yoshikuni Edagawa, Hiroshi Saito, Kazuho Abe

Research output: Contribution to journalArticle

45 Citations (Scopus)

Abstract

The primary visual cortex shows synaptic plasticity during a postnatal "critical period," and its plasticity declines with development. Indeed, we found a developmental decrease in the induction of long-term potentiation (LTP) in the rat visual cortex. In visual cortex slices obtained from 2- to 3-week-old rats, tetanic stimulation (100 Hz for 1 sec, twice at an interval of 30 sec) of the white matter reproducibly induced LTP of field potentials in layer II/III. However, in slices from 5-week-old rats, the same tetanic stimulation failed to induce LTP. We hypothe-sized that endogenous serotonin (5-HT) is responsible for the developmental decrease in visual cortex LTP, because the induction of visual cortex LTP was suppressed by the addition of exogenous 5-HT (10 μM) and because the amount of 5-HT in the visual cortex increased during development. To test this hypothesis, we investigated the effect of methysergide, a 5-HT receptor antagonist, on the induction of visual cortex LTP. When visual cortex slices from 5-week-old rats were perfused with 50 μM methysergide, tetanic stimulation of the white matter induced robust LTP in layer II/III. Furthermore, serotonergic neurons were lesioned by intracerebroventricular injection of 5,7-dihydroxytryptamine (5,7-DHT). LTP was induced in visual cortex slices from 5,7-DHT-treated, 5-week-old rats. These results suggest that the induction of visual cortex LTP in 5-week-old rats is suppressed by endogenous 5-HT. 5-HT may be a factor that determines a critical period for synaptic plasticity in the rat visual cortex.

Original languageEnglish
Pages (from-to)1532-1537
Number of pages6
JournalJournal of Neuroscience
Volume21
Issue number5
Publication statusPublished - 2001 Mar 1

Keywords

  • Field potential
  • Long-term potentiation
  • Postnatal development
  • Rat
  • Serotonin
  • Visual cortex

ASJC Scopus subject areas

  • Neuroscience(all)

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