Lasting increase in serotonin 5-HT(1A) but not 5-HT4 receptor subtypes in the kindled rat dentate gyms: Dissociation from local presynaptic effects

A. Cagnotto, D. Crespi, L. Mancini, C. Manzoni, M. L. Presti, M. Gariboldi, A. Vezzani, T. Mennini

Research output: Contribution to journalArticlepeer-review

Abstract

We examined the effect of kindling on serotonergic neurotransmission in the hippocampus by measuring serotonin (5-HT) release and uptake in hippocampal synaptosomes and 5-HT(1A) and 5-HT4 receptor subtypes during and at different times after electrical kindling of the dentate gyrus. Using quantitative receptor autoradiography, we found that binding of 8- [3H]hydroxy-2-(di-n-propylamino)tetralin ([3H]8-OH-DPAT) to 5-HT(1A) receptors was selectively increased by 20% on average (p <0.05) in the dentate gyrus of the stimulated and contralateral hippocampus 2 days after stage 2 (stereo-types and occasional retraction of a forelimb) and by 100% on average (p <0.05) 1 week after stage 5 (tonic-clonic seizures) compared with sham-stimulated rats. A 20% increase (p <0.05) was observed 1 month after the last generalized seizure. No changes were found after a single afterdischarge. 5-HT4 receptors, which colocalize with 5-HT(1A) receptors on hippocampal neurons, were not modified in kindled tissue. [3H]5-HT uptake and its release as well as the 5-HT(1B) autoreceptor function did not differ from shams in hippocampal synaptosomes at stages 2 and 5. Systemic administration of 100 and 1,000 μg kg-1 8-OH-DPAT or 1,000 μg kg-1 WAY- 100,635, 30 rain before each electrical stimulation, did not significantly alter kindling progression or the occurrence of stage 5 seizures in fully kindled rats. The changes in 5-HT(1A) receptor density in the dentate gyrus are part of the plastic modifications occurring during kindling and may contribute to modulating tissue hyperexcitability.

Original languageEnglish
Pages (from-to)850-857
Number of pages8
JournalJournal of Neurochemistry
Volume70
Issue number2
Publication statusPublished - Feb 1998

Keywords

  • 8- Hydroxy-2-(di-n-propylamino)tetralin
  • Electrical kindling
  • Hippocampus
  • Rat
  • Receptor autoradiography
  • Seizures
  • Serotonin 5-HT(1A) and 5-HT receptor subtypes
  • WAY 100,635

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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