Mild Hyperoxia Stimulation Increases Regional Tissue Oxygen Pressure in Rat Hippocampus via Oxygen Radical
H. Yoshizato *
Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso-cyo, Showa-ku, Nagoya, 466-8555, Japan.
Osung Kwon
School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul, South Korea.
S. Ato
Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso-cyo, Showa-ku, Nagoya, 466-8555, Japan.
R. Ogasawara
Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso-cyo, Showa-ku, Nagoya, 466-8555, Japan.
Y. Hanai
Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso-cyo, Showa-ku, Nagoya, 466-8555, Japan.
Y. Yoshimura
Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso-cyo, Showa-ku, Nagoya, 466-8555, Japan.
*Author to whom correspondence should be addressed.
Abstract
Aims: The purpose of this study is to examine a rise of the local tissue oxygen pressure in hippocampus (Hip-pO2) which means neuronal activation by mild hyperoxia through oxygen radical.
Study Design: Study was an animal experiment with rat.
Place and Duration of Study: Department of Department of Life Science and Applied Chemistry, Nagaya Institute of Technology, between January 2014 and January 2018.
Methodology: Rats were exposed to air or mild oxygen gas. At the same time, Local tissue oxygen pressure in hippocampus (Hip-pO2) were measured for 20 min with or without treatment of two type of radical scavengers.
Results: The Hip-pO2 levels were significantly increased by mild hyperoxia exposure (50-60% above resting level). The mild hyperoxia-induced enhancement of the Hip-pO2 levels were inhibited by MnTMPyP (radical scavenger), but not by NADPH oxidase (NOX) inhibitor Apocynin.
Conclusion: These findings suggested that mild hyperoxia could activate hippocampus through generation of oxygen radicals.
Keywords: Mild hyperoxia, oxygen gas, reactive oxygen species, MnTMPyP, apocynin, Hip-pO2, neural activation, clark-type electrode.