Abstract
Rationale: Although chronic use of methamphetamine (METH) leads to long-lasting cognitive dysfunction in humans, there are few reports about an animal model that reflects METH-induced impairment of working memory. Objectives: In this study, we investigated the effect of repeated METH treatment on spatial working memory in rats. Materials and methods: Rats were repeatedly administered METH (2 mg/kg) once a day for 7 days, and their memory function was assessed with a delayed spatial win-shift task in a radial arm maze. The task consisted of two phases, a training phase and a test phase, separated by a delay. Results: METH-treated animals showed an impairment of performance in the test phase when the delay time was increased from 5 to 30 min or longer. The effect of METH persisted for at least 14 days after the drug withdrawal. METH-induced impairment of working memory was reversed by clozapine (3 and 10 mg/kg, for 7 days), but not haloperidol (1 and 2 mg/kg, for 7 days). The improving effect of clozapine diminished 7 days after the withdrawal. Phosphorylated extracellular signal-regulated kinase1/2 (ERK1/2) levels were significantly increased in the hippocampus of saline-treated control rats from 5 to 60 min after the training phase. In contrast, hyperphosphorylation of ERK1/2 was abolished in the hippocampus of rats treated with METH. Conclusions: These findings suggest that repeated METH treatment induces impairment of working memory, which is associated with a dysfunctional ERK1/2 pathway in the hippocampus. Furthermore, clozapine may be effective for the treatment of METH-induced cognitive dysfunction.
| Original language | English |
|---|---|
| Pages (from-to) | 21-32 |
| Number of pages | 12 |
| Journal | Psychopharmacology |
| Volume | 194 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 01-09-2007 |
| Externally published | Yes |
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All Science Journal Classification (ASJC) codes
- Pharmacology
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Repeated methamphetamine treatment impairs spatial working memory in rats : Reversal by clozapine but not haloperidol. / Nagai, Taku; Takuma, Kazuhiro; Dohniwa, Misato; Ibi, Daisuke; Mizoguchi, Hiroyuki; Kamei, Hiroyuki; Nabeshima, Toshitaka; Yamada, Kiyofumi.
In: Psychopharmacology, Vol. 194, No. 1, 01.09.2007, p. 21-32.Research output: Contribution to journal › Article
TY - JOUR
T1 - Repeated methamphetamine treatment impairs spatial working memory in rats
T2 - Reversal by clozapine but not haloperidol
AU - Nagai, Taku
AU - Takuma, Kazuhiro
AU - Dohniwa, Misato
AU - Ibi, Daisuke
AU - Mizoguchi, Hiroyuki
AU - Kamei, Hiroyuki
AU - Nabeshima, Toshitaka
AU - Yamada, Kiyofumi
PY - 2007/9/1
Y1 - 2007/9/1
N2 - Rationale: Although chronic use of methamphetamine (METH) leads to long-lasting cognitive dysfunction in humans, there are few reports about an animal model that reflects METH-induced impairment of working memory. Objectives: In this study, we investigated the effect of repeated METH treatment on spatial working memory in rats. Materials and methods: Rats were repeatedly administered METH (2 mg/kg) once a day for 7 days, and their memory function was assessed with a delayed spatial win-shift task in a radial arm maze. The task consisted of two phases, a training phase and a test phase, separated by a delay. Results: METH-treated animals showed an impairment of performance in the test phase when the delay time was increased from 5 to 30 min or longer. The effect of METH persisted for at least 14 days after the drug withdrawal. METH-induced impairment of working memory was reversed by clozapine (3 and 10 mg/kg, for 7 days), but not haloperidol (1 and 2 mg/kg, for 7 days). The improving effect of clozapine diminished 7 days after the withdrawal. Phosphorylated extracellular signal-regulated kinase1/2 (ERK1/2) levels were significantly increased in the hippocampus of saline-treated control rats from 5 to 60 min after the training phase. In contrast, hyperphosphorylation of ERK1/2 was abolished in the hippocampus of rats treated with METH. Conclusions: These findings suggest that repeated METH treatment induces impairment of working memory, which is associated with a dysfunctional ERK1/2 pathway in the hippocampus. Furthermore, clozapine may be effective for the treatment of METH-induced cognitive dysfunction.
AB - Rationale: Although chronic use of methamphetamine (METH) leads to long-lasting cognitive dysfunction in humans, there are few reports about an animal model that reflects METH-induced impairment of working memory. Objectives: In this study, we investigated the effect of repeated METH treatment on spatial working memory in rats. Materials and methods: Rats were repeatedly administered METH (2 mg/kg) once a day for 7 days, and their memory function was assessed with a delayed spatial win-shift task in a radial arm maze. The task consisted of two phases, a training phase and a test phase, separated by a delay. Results: METH-treated animals showed an impairment of performance in the test phase when the delay time was increased from 5 to 30 min or longer. The effect of METH persisted for at least 14 days after the drug withdrawal. METH-induced impairment of working memory was reversed by clozapine (3 and 10 mg/kg, for 7 days), but not haloperidol (1 and 2 mg/kg, for 7 days). The improving effect of clozapine diminished 7 days after the withdrawal. Phosphorylated extracellular signal-regulated kinase1/2 (ERK1/2) levels were significantly increased in the hippocampus of saline-treated control rats from 5 to 60 min after the training phase. In contrast, hyperphosphorylation of ERK1/2 was abolished in the hippocampus of rats treated with METH. Conclusions: These findings suggest that repeated METH treatment induces impairment of working memory, which is associated with a dysfunctional ERK1/2 pathway in the hippocampus. Furthermore, clozapine may be effective for the treatment of METH-induced cognitive dysfunction.
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U2 - 10.1007/s00213-007-0820-1
DO - 10.1007/s00213-007-0820-1
M3 - Article
VL - 194
SP - 21
EP - 32
JO - Psychopharmacology
JF - Psychopharmacology
SN - 0033-3158
IS - 1
ER -