Opposite effects induced by low and high doses of apomorphine on single-trial passive avoidance learning in mice

Kenji Ichihara, Toshitaka Nabeshima, Tsutomu Kameyama

研究成果: Article査読

51 被引用数 (Scopus)

抄録

The effects of apomorphine (0.0125-1 mg/kg, SC), a dopamine (DA) agonist, on passive avoidance learning were assessed in mice which received brief and long foot-shocks in a training test. At low doses, apomorphine stimulates DA autoreceptors. With a shock of brief duration, apomorphine at a low dose (0.05 mg/kg), enhanced the avoidance learning when it was administered 20 min before the training test or the retention test. At high doses, apomorphine stimulates postsynaptic DA receptors. With a shock of long duration, apomorphine at a high dose (1 mg/kg), impaired the avoidance learning when it was administered 20 min before the training test or the retention test. However, apomorphine (0.05 and 1 mg/kg) given immediately after the training test did not have any effect on the avoidance behavior with shocks of either brief or long durations. Apomorphine-induced enhancement of passive avoidance learning was antagonized by sulpiride, but not by haloperidol. These results show that apomorphine induced the opposite effects on the passive avoidance learning depending on the dose or on the reinforcement intensity and suggest that the central DA system may play an important role in modulating memory processes.

本文言語English
ページ(範囲)107-113
ページ数7
ジャーナルPharmacology, Biochemistry and Behavior
30
1
DOI
出版ステータスPublished - 05-1988
外部発表はい

All Science Journal Classification (ASJC) codes

  • 生化学
  • 毒物学
  • 薬理学
  • 臨床生化学
  • 生物学的精神医学
  • 行動神経科学

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