Presynaptic 5-HT1A receptors mediate the effect of ipsapirone on punished responding in rats

Luigi Cervo, Rosario Samanin

Research output: Contribution to journalArticle

Abstract

The effect of ipsapirone, a partial agonist at 5-HT1A receptors, and of idazepam on punished operant responding was studied in rats injected intracerebroventricularly with 150 μg 5,7-dihydroxytryptamine to deplete brain serotonin or pretreated with (S)-WAY 100135 (N-tert-butyl 3-4-(2-methoxyphenyl)piperazin-1-yl-2-phenylpropanamide dihydrochloride), an antagonist at 5-HT1A receptors. 5,7-Dihydroxytryptamine markedly depleted brain serotonin and caused a sustained increase in punished responding with no effect on rates of unpunished responding. Rates of punished responding returned to control values about 2 weeks after 5,7-dihydroxytryptamine. At doses ranging from 2.5 to 10 mg/kg s.c. ipsapirone significantly increased the rates of punished responding in sham-operated rats but had no effect in animals which had received 5,7-dihydroxytryptamine. At 5 and 10 mg/kg ipsapirone reduced unpunished responding similarly in sham-operated and 5,7-dihydroxytryptamine-treated rats. Diazepam 2.5 mg/kg i.p. significantly increased punished responding and reduced rates of unpunished responding similarly in sham-operated and in 5,7-dihydroxytryptamine-treated animals. At 3 and 10 mg/kg (S)-WAY 100135 did not modify punished or unpunished responding but at 10 mg/kg it completely antagonized the effect of 5 mg/kg s.c. ipsapirone on unpunished and punished responding. The results suggest that ipsapirone releases behaviour that is suppressed by punishment by stimulating presynaptic 5-HT1A receptors.

Original languageEnglish
Pages (from-to)249-255
Number of pages7
JournalEuropean Journal of Pharmacology
Volume284
Issue number3
DOIs
Publication statusPublished - Sep 25 1995

Keywords

  • (S)-WAY 100135
  • 5-HT receptor
  • Anxiolytic activity
  • Conflict
  • Ipsapirone
  • Punishment

ASJC Scopus subject areas

  • Pharmacology
  • Cellular and Molecular Neuroscience

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