Interactive effects of morphine and dopaminergic compounds on spatial working memory in rhesus monkeys.
Opiates and dopamine (DA) play key roles in learning and memory in humans and animals. Although interactions between these neurotransmitters have been found, their functional roles remain to be fully elucidated, and their dysfunction may contribute to human diseases and addiction. Here we investigated the interactions of morphine and dopaminergic neurotransmitter systems with respect to learning and memory in rhesus monkeys by using the Wisconsin General Test Apparatus (WGTA) delayed-response task. Morphine and DA agonists (SKF-38393, apomorphine and bromocriptine) or DA antagonists (SKF-83566, haloperidol and sulpiride) were co-administered to the monkeys 30 min prior to the task. We found that dose-patterned co-administration of morphine with D1 or D2 antagonists or agonists reversed the impaired spatial working memory induced by morphine or the compounds alone. For example, morphine at 0.01 mg/kg impaired spatial working memory, while morphine (0.01 mg/kg) and apomorphine (0.01 or 0.06 mg/kg) co-treatment ameliorated this effect. Our findings suggest that the interactions between morphine and dopaminergic compounds influence spatial working memory in rhesus monkeys. A better understanding of these interactive relationships may provide insights into human addiction.
State Key Laboratory of Brain and Cognitive Sciences, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China. wangjh@mail.kiz.ac.cn
Jian-Hong
JH
Wang
Joshua Dominie
JD
Rizak
Yan-Mei
YM
Chen
Liang
L
Li
Xin-Tian
XT
Hu
Yuan-Ye
YY
Ma
D000818:Animals; D001245:Association Learning / Q000187:drug effects*; D001522:Behavior, Animal / Q000187:drug effects; D015259:Dopamine Agents / Q000008:administration & dosage*; D004347:Drug Interactions; D058999:Drug-Seeking Behavior / Q000502:physiology; D008253:Macaca mulatta; D008297:Male; D008570:Memory, Short-Term / Q000187:drug effects* / Q000502:physiology; D009020:Morphine / Q000008:administration & dosage*; D011897:Random Allocation; D011930:Reaction Time; D011954:Receptors, Dopamine / Q000187:drug effects / Q000502:physiology*; D013037:Spatial Behavior / Q000187:drug effects* / Q000502:physiology
D015259:Dopamine Agents; D011954:Receptors, Dopamine; D009020:Morphine