Blockade of muscarinic receptors impairs the retrieval of well-trained memory

摘要: Acetylcholine (ACh) is known to play an important role in memory functions, and its deficit has been proposed cause the cognitive decline associated with advanced age Alzheimer’s disease (the cholinergic hypothesis). Although many studies have tested hypothesis for recently acquired memory, only a few investigated of ACh retrieval process well-trained which describes established from repetition daily routine. To examine this point, we trained rats perform two-alternative forced-choice visual detection task. Each trial was started by having pull upward central-lever, triggered presentation stimulus right or left side display monitor, then pulling stimulus-relevant choice-lever located on both sides. Rats learned task within 10 days, training continued month. Task performance measured without systemic administration muscarinic receptor (mAChR) antagonist, scopolamine (SCOP), prior test. After 30 min SCOP administration, stopped manipulating any lever even though they explored surrounding environment, suggesting loss task-related associative memory. Three hours later, were recovered complete trial, but selected levers irrespective stimulus, remembered series lever-manipulations association reward, not between reward stimulation. Furthermore, m1-AChR, nicotinic AChR antagonist caused similar execution. neither interfered locomotor activity nor drinking behavior, while it influenced anxiety. These results suggest that activation mAChRs at basal levels essential recall