Nitric oxide （NO） is a novel type of neurotransmitter that is closely associated with synaptic plasticity, learning and memory. In the present study, we assessed the effects of Larginine and NnitroL arginine methyle...Nitric oxide （NO） is a novel type of neurotransmitter that is closely associated with synaptic plasticity, learning and memory. In the present study, we assessed the effects of Larginine and NnitroL arginine methylester （LNAME, a nitric oxide synthase inhibitor） on learning and memory. Rats were assigned to three groups receiving intracerebroventricular injections of LArg （the NO precursor）, LNAME, or 0.9% NaCI （control）, once daily for seven con secutive days. Twelve hours after the last injection, they underwent an electric shockpaired Y maze test. Twentyfour hours later, the rats＇ memory of the safe illuminated arm was tested. After that, the levels of NO and a7 nicotinic acetylcholine receptor （a7 nAChR） in the prefrontal cortex and hippocampus were assessed using an NO assay kit, and immunohistochemistry and Western blots, respectively. We found that, compared to controls, LArgtreated rats received fewer foot shocks and made fewer errors to reach the learning criterion, and made fewer errors during the memorytesting session. In contrast, LNAMEtreated rats received more foot shocks and made more errors than controls to reach the learning criterion, and made more errors during the memorytesting session. In parallel, NO content in the prefrontal cortex and hippocampus was higher in LArgtreated rats and lower inLNAME rats, compared to controls. Similarly, （]7 nAChR immunoreactivity and protein expression in the prefrontal cortex and hippocampus were higher in LArgtreated rats and lower in LNAME rats, compared to controls. These results suggest that the modulation of NO content in the brain correlates with a7 nAChR distribution and expression in the prefrontal cortex and hippocampus, as well as with learning and memory performance in the Ymaze.展开更多
基金supported by Undergraduate Innovational Experimentation Program of Shanxi Province, China (2009103)
文摘Nitric oxide （NO） is a novel type of neurotransmitter that is closely associated with synaptic plasticity, learning and memory. In the present study, we assessed the effects of Larginine and NnitroL arginine methylester （LNAME, a nitric oxide synthase inhibitor） on learning and memory. Rats were assigned to three groups receiving intracerebroventricular injections of LArg （the NO precursor）, LNAME, or 0.9% NaCI （control）, once daily for seven con secutive days. Twelve hours after the last injection, they underwent an electric shockpaired Y maze test. Twentyfour hours later, the rats＇ memory of the safe illuminated arm was tested. After that, the levels of NO and a7 nicotinic acetylcholine receptor （a7 nAChR） in the prefrontal cortex and hippocampus were assessed using an NO assay kit, and immunohistochemistry and Western blots, respectively. We found that, compared to controls, LArgtreated rats received fewer foot shocks and made fewer errors to reach the learning criterion, and made fewer errors during the memorytesting session. In contrast, LNAMEtreated rats received more foot shocks and made more errors than controls to reach the learning criterion, and made more errors during the memorytesting session. In parallel, NO content in the prefrontal cortex and hippocampus was higher in LArgtreated rats and lower inLNAME rats, compared to controls. Similarly, （]7 nAChR immunoreactivity and protein expression in the prefrontal cortex and hippocampus were higher in LArgtreated rats and lower in LNAME rats, compared to controls. These results suggest that the modulation of NO content in the brain correlates with a7 nAChR distribution and expression in the prefrontal cortex and hippocampus, as well as with learning and memory performance in the Ymaze.
