Dopaminergic Involvement in Improving Effects of Dynorphin A-(1-13) on Galanin-Induced Impairment of Passive Avoidance Learning in Mice
✍ Scribed by MAKOTO UKAI; MASATAKA MIURA; TSUTOMU KAMEYAMA
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 137 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0885-6222
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✦ Synopsis
The present study was designed to clarify whether dopaminergic systems are involved in the eects of dynorphin A-(1-13), an endogenous k-opioid receptor agonist, on the galanin-induced impairment of passive avoidance learning in mice. Galanin (0Á3 mg, i.c.v.) shortened step-down latency of passive avoidance learning, while the dopamine D 1 receptor agonist SKF 38393 (3 and 10 mg/kg, s.c.), the dopamine D 2 receptor agonist RU 24213 (0 . 3 and 1 mg/kg, s.c.), the dopamine D 1 receptor antagonist SCH 23390 (0 . 01 and 0 . 03 mg/kg, i.p.) or the dopamine D 2 receptor antagonist SÀ-sulpiride (10 and 30 mg/kg, i.p.) failed to in¯uence it. Dynorphin A-(1-13) (3 mg, i.c.v.) and SKF 38393 (10 mg/kg, s.c.) markedly improved the galanin (0Á3 mg, i.c.v.)-induced shortening of step-down latency. However, RU 24213 (0 . 3 and 1 mg/kg, s.c.), SCH 23390 (0 . 01 and 0 . 03 mg/kg, i.p.) or SÀ-sulpiride (10 and 30 mg/kg, i.p.) did not aect the galanin (0Á3 mg, i.c.v.)-induced shortening of step-down latency. In contrast, SCH 23390 (0 . 3 mg/kg, i.p.) signi®cantly reversed the improving eects of dynorphin A-(1-13) (3 mg, i.c.v.) on the galanin (0Á3 mg, i.c.v.)-induced dysfunction of passive avoidance learning, although SKF 38393 (1 and 3 mg/kg, s.c.), RU 24213 (0 . 3 and 1 mg/kg, s.c.) or SÀ-sulpiride (10 and 30 mg/kg, i.p.) did not in¯uence the eects of dynorphin A-(1-13) (3 mg, i.c.v.). These results suggest that dynorphin A-(1-13) improves the galanin-induced amnesia resulting from indirect stimulation of dopamine D 1 receptors.