Depressive behavior and alterations in receptors for dopamine and 5-hydroxytryptamine in the brain of the senescence accelerated mouse (SAM)-P10

T. Onodera, R. Watanabe, K. K. Tha, Y. Hayashi, T. Murayama, Y. Okuma, C. Ono, Y. Oketani, M. Hosokawa, Y. Nomura

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The senescence accelerated mouse (SAM) is known as a murine model of aging. SAM consists of senescence accelerated-prone mouse (SAMP) and senescence accelerated-resistant mouse (SAMR). Previous studies reported that SAMP10 exhibits age-related learning impairments and behavioral depression in a tail suspension test after 7 months. We investigated the changes in emotional behavior in a forced swimming test and in receptors for dopamine and 5-hydroxytryptamine (5-HT) in SAMPO10. SAMP10 at 8 months showed an increase of immobility in the test compared with SAMR1. Treatment with desipramine (25 mg/kg, i.p., 3 days) in SAMP10 caused a decrease in immobility. In the cortex from SAMP10, [3H]quinpirole binding to D2/D3 dopamine receptors increased significantly compared with control SAMR1. In the hippocampus from SAMP10, [3H]8-hydroxy DPAT binding to 5-HT(1A) receptor increased. In midbrains from SAMP10, bindings of [3H]quinpirole and [3H]8-hydroxy DPAT increased. [3H]SCH23390 binding to D1/D5 receptors and [3H]ketanserin binding to 5-HT2 receptor in brain regions examined SAMP10 in were similar to those in SAMR1. The present findings represent the first neurochemical evidence of an increase of D2/D3 and 5-HT(1A) receptors in SAMP10. SAMP10 may be a useful model of aging associated depressive behavior.

Original languageEnglish
Pages (from-to)312-318
Number of pages7
JournalJapanese Journal of Pharmacology
Issue number4
Publication statusPublished - 2000
Externally publishedYes


  • 5-Hydroxytryptamine
  • Depression
  • Dopamine
  • Receptor
  • Senescence accelerated mouse

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