Effects of 7-NI and ODQ on memory in the passive avoidance, novel object recognition, and social transmission of food preference tests in mice

Abstract

BackgroundNitric oxide (NO) is an intercellular messenger that plays a critical role in learning and memory processes. Effects of nitric oxide synthase (NOS) inhibitors and guanylate cyclase (GC) inhibitors on cognitive function remain controversial.Material/MethodsThe aim of this study was to investigate effects of an NOS inhibitor, 7-nitroindazole (7-NI), and a GC inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), on different aspects of memory in passive avoidance (PA), novel object recognition (NOR), and social transmission of food preference (STFP) tests. Male Balb-c mice were treated intraperitoneally with 7-NI (15 mg/kg), ODQ (3,10 mg/kg), L-arginine (100 mg/kg) + 7-NI (15 mg/kg), or physiological saline.ResultsODQ (10 mg/kg) and 7-NI (15 mg/kg) significantly decreased second-day latency in PA test. 7-NI (15 mg/kg) and ODQ (10 mg/kg) significantly decreased the ratio index in the NOR test. 7-NI and ODQ (10 mg/kg) decreased cued/non-cued food eaten in STFP test. Amount of time spent in center zone significantly increased in ODQ (10 mg/kg) and 7-NI (15 mg/kg) groups in open field test, but there was no effect on total distance moved and speed of animals. ODQ (10 mg/kg) significantly increased number of entries into new compartments in exploratory activity apparatus, while 7-NI had no effect. Administration of L-arginine (100 mg/kg) before 7-NI reversed 7-NI-induced effects, supporting the role of NO in cognition.ConclusionsOur results confirm that inhibition of NO/cGMP/GS pathway might disturb emotional, visual, and olfactory memory in mice. Also, 7-NI and ODQ had anxiolytic effects in open field test, and ODQ also enhanced exploratory activity.

In Search of Memory Tests Equivalent for Experiments on Animals and Humans

“…Some of these investigations concern the essence of the processes of data remembering and retrieval. For instance, Akar et al presented results that confirm the thesis that inhibition of nitric oxide synthetase disturbs emotional, visual, and olfactory memory in mice [ 1 ].…”

“…Akar et al used 5 tests of memory in their experiments: Novel Object Recognition Test (NORT), Passive Avoidance Test (PA), Social Transmission of Food Preference Test (STFP), Open Field Test, and Free Exploratory Paradigm [ 1 ]. The administration of NORT and PA test are illustrated in Figures 2 and 3 .…”

“…Careful analysis of the above-mentioned investigations performed on humans and animals leads us to propose that the most appropriate candidate for testing memory in both humans and animals is the Novel Object Recognition Test (NORT), which was used by Akar et al [ 1 ]. We conclude this based on the description of this test by Ennaceur and Delacour [ 34 ].…”

Lipopolysaccharide-induced memory impairment in rats is preventable using 7-nitroindazole

“…It has been suggested that overproductions of NO take place due to activation of nNOS by the stimuli such as endotoxins and cytokines 9 . It has also been reported that both nNOS and eNOS isoforms affect learning and memory 10 . 7-nitroindazol (7NI) has been considered as a selective nNOS inhibitor as well as a nonselective NOS inhibitors (nNOS/eNOS) 10,11 .…”

“…It has also been reported that both nNOS and eNOS isoforms affect learning and memory 10 . 7-nitroindazol (7NI) has been considered as a selective nNOS inhibitor as well as a nonselective NOS inhibitors (nNOS/eNOS) 10,11 . It has been shown that 7NI induces learning and memory deficits in different behavioral experiments such as, Morris water maze(MWM), radial maze, passive avoidance (PA) and elevated plus maze tests 12 .…”