Reversal of morphine-induced memory impairment in mice by withdrawal in Morris water maze: possible involvement of cholinergic system.
The effects of morphine and morphine withdrawal on memory performance were examined in mice by using Morris water maze task. Morphine-induced memory impairment at the doses of 5 and 10 mg/kg recovered after repeated administration. Oxotremorine, a muscarinic receptor agonist, at the dose of 0.1 mg/kg ip, and physostigmine, a cholinesterase inhibitor, at the dose of 0.1 mg/kg ip, significantly antagonized morphine (10 mg/kg sc)-induced memory impairment in mice. Furthermore, repeated naloxone (0.5 mg/kg ip) attenuated scopolamine (0.2 mg/kg ip)-induced memory impairment. By using escalating doses of morphine for 13 days, morphine-induced memory impairment was continuously maintained. When withdrawal was precipitated by naloxone (5 mg/kg ip), or administration of oxotremorine (0.1 and 0.2 mg/kg ip) or physostigmine (0.05 and 0.1 mg/kg ip), the impairment was completely reversed. These results suggest that morphine-induced memory impairment could be partially due to the inhibition of the central cholinergic activity.
Li
Z
Z
Department of Pharmacology, Shenyang Pharmaceutical University, 110015, Shenyang, People's Republic of China.
Wu
C F
CF
Pei
G
G
Xu
N J
NJ
D000818:Animals; D018680:Cholinergic Antagonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007279:Injections, Subcutaneous; D008297:Male; D018782:Maze Learning / Q000187:drug effects*; D008569:Memory Disorders / Q000139:chemically induced* / Q000523:psychology; D051379:Mice; D009020:Morphine / Q000008:administration & dosage / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D009042:Motivation; D018721:Muscarinic Agonists / Q000494:pharmacology; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology*; D009294:Narcotics / Q000009:adverse effects / Q000494:pharmacology*; D010095:Oxotremorine / Q000494:pharmacology; D010275:Parasympathetic Nervous System / Q000502:physiology*; D010830:Physostigmine / Q000494:pharmacology; D012601:Scopolamine / Q000494:pharmacology; D013375:Substance Withdrawal Syndrome / Q000523:psychology
D018680:Cholinergic Antagonists; D018721:Muscarinic Agonists; D018727:Muscarinic Antagonists; D009292:Narcotic Antagonists; D009294:Narcotics; D009270:Naloxone; D010095:Oxotremorine; D009020:Morphine; D010830:Physostigmine; D012601:Scopolamine