神经系统编码（胡新天）知识库

Honeybee is a widely used insect model for learning and memory research. Recently, it has become a potentially good subject for evaluating the effects of addictive drugs on the nervous systems. Our previous study has found that acute morphine injection affected associative memory and locomotor activity in honeybees. In the current study, the effect of chronic morphine treatment and its cessation in honeybees were assessed. The results demonstrated that 1) chronic morphine (0.01, 0.1 and 1 mg/ml) treatment for 7 days severely diminished associative memory in honeybees; 2) 1 mg/ml morphine consumption for 5, 7 and 10 but not 3 days impaired the olfactory memory; 3) Bees withdrawn from morphine for 1 day but not 3 days showed amnesia in the PER conditioning. We also found that bees displayed hyperactivity and tolerance in response to chronic morphine administration. In addition, morphine dose-dependently altered the sucrose responsiveness of bees. The data indicated that chronic morphine has sensory-motor effects and may impair learning and/or memory in honeybees, which were comparative to that in vertebrates.