Intraamygdaloid microinjection of acylated-ghrelin influences passive avoidance learning

Krisztián Tóth, Kristóf László, Edit Lukács, László Lénárd

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

The brain-gut peptide acylated-ghrelin (A-Ghr) is a potent growth hormone (GH) secretagogue substance. A-Ghr is also known to influence on memory and learning processes. Its effect is mediated partly via GH secretagogue receptor (GHS-R) type 1a. The amygdaloid body (AMY) plays important role in memory and learning processes. Projections of ghrelinergic neurons were identified in the AMY, and previously we verified that A-Ghr infused into basolateral nucleus of the AMY (ABL) caused liquid food intake decrease. The aim of the present study was to examine the possible effects of A-Ghr in the ABL on learning. Male Wistar rats were examined in two-compartment passive avoidance paradigm. Animals were shocked with 0.4 mA current and subsequently were microinjected bilaterally with 50 or 100 ng A-Ghr, 30 ng GHS-R antagonist d-Lys3-GHRP-6 (ANT), ANT + 50 ng A-Ghr (dissolved in 0.15 M sterile NaCl/0.4 μl) or vehicle into the ABL. Fifty nanogram A-Ghr significantly increased the latency time, the 100 ng and the ANT alone were ineffective. The effect of 50 ng A-Ghr was eliminated by the ANT pretreatment. Our results suggest that intraamygdaloid A-Ghr enhances learning processes and memory in aversive situations, and this effect can specifically be prevented by ANT pretreatment.

Original languageEnglish
Pages (from-to)308-311
Number of pages4
JournalBehavioural Brain Research
Volume202
Issue number2
DOIs
Publication statusPublished - Sep 14 2009

Keywords

  • Amygdaloid body
  • Ghrelin
  • Memory
  • Passive avoidance learning

ASJC Scopus subject areas

  • Behavioral Neuroscience

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