THE EFFECTS OF NITRIC OXIDE WITHIN THE DORSAL HIPPOCAMPUS ON SPATIAL LEARNING AND MEMORY IN MALE NMRI STRESSED MICE

Sahraei, Mohammad; Mashhadi, Atusa; Meftahi, Hossein

doi:10.21608/bfsa.2022.239626

THE EFFECTS OF NITRIC OXIDE WITHIN THE DORSAL HIPPOCAMPUS ON SPATIAL LEARNING AND MEMORY IN MALE NMRI STRESSED MICE

Document Type : Original Article

Authors

¹ School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran

² Department of Biology, North Tehran branch, Islamic Azad University, Tehran, Iran

³ Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran

10.21608/bfsa.2022.239626

Abstract

Nitric oxide is an essential neurotransmitter in the hippocampus involved in spatial learning and memory and response to stress. This study investigated the effects of nitric oxide within the dorsal hippocampus on spatial learning and memory in male NMRI stressed mice. Male NMRI (Naval Medical Research Institute) mice (n= 7/group) were divided into; Saline, L-NAME (L-Nitro-Arginine Methyl Ester) (1, 5, 10 µg/mouse), and L-Arginine (1, 5, 10 µg/mouse) groups. Seven days after bilateral intra dorsal hippocampus cannulation, half of the animals received electro foot shock stress once/day, for four consecutive days. Barnes maze method was applied for the evaluation of stress effects on spatial learning and memory. Elapsed time and distance traveled to reach the target hole, and the numbers of errors were calculated as spatial learning and memory performance indicators. Stress increases the time and distance for reaching the target hole. The number of errors also was increased in the stress group. Intra dorsal hippocampus administration of L-arginine reduced the stress-induced spatial learning and memory deficit. The drug reduced the time and distance for reaching the target hole. L-NAME also reduced the stress effect. The drug reduced the time and distance for reaching the target hole. Since both the inhibition of NO synthesis and increasing the NO synthesis in the dorsal hippocampus resulted in learning and memory improvements in mice exposed to electro foot shock stress, NO in the dorsal hippocampus might be involved in stress-related spatial learning and memory deficits.

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