Objective: In this experiment, the effects of dopaminergic drugs on morphine state dependent memory were examined in mice, based on the passive avoidance task.
Method: In this experimental research, morphine and saline were administered subcutaneously, and dopaminergic drugs were administered cerebroventricularly (into the brain). Then (using Passive Avoidance Apparatus) step-down latency was measured, which shows the memory of the animal.
Results: Pre- training subcutaneous administration of morphin (5mg/kg) led to the impairment of retrieval memory but the administration of the same dose on the test day led to state-dependent memory (learning). The pre-test intracerebroventricular (ICV) administration of the D1 agonist (SKF 38393), D2 agonist (quinpirole) and D2 blocker (sulpiride) not only mimiced the effect of pre-test morphine treatment, but also increased the function of opioids. Furthermore, the pre-test ICV administration of D1 antagonist (SCH 23390) prevented the restoration of memory by morphine.
Conclusion: Effects of mrphine on some memory pathways seems to be induced through dopamine receptors.
Type of Study:
Research |
Subject:
Special Received: 2004/11/11 | Accepted: 2005/01/10 | Published: 2005/03/21