Theophylline attenuates microwave-induced impairment of memory acquisition

• Published in: Neuroscience letters Vol. 412; no. 2; pp. 129 - 133
• Main Authors: Xu, Zhi-Wei, Hou, Bing, Li, Yun-Feng, Gao, Yan, Su, Zhen-Tao, Yang, Guo-Shan, Zhao, Shi-Fu, He, Fu-Chu, Zhang, Cheng-Gang
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 29.01.2007; Elsevier
• Subjects: Adenosine; Adenosine - metabolism; Animals; Avoidance Learning - drug effects; Avoidance Learning - radiation effects; Biological and medical sciences; Body Temperature - radiation effects; Fever - etiology; Fever - metabolism; Fever - physiopathology; Fundamental and applied biological sciences. Psychology; Hippocampus - drug effects; Hippocampus - physiopathology; Hippocampus - radiation effects; Inhibitory avoidance task; Male; Memory - drug effects; Memory - radiation effects; Memory Disorders - drug therapy; Memory Disorders - etiology; Memory Disorders - physiopathology; Memory impairment; Mice; Microwave; Microwaves - adverse effects; Phosphodiesterase Inhibitors - therapeutic use; Purinergic P1 Receptor Antagonists; Radiation Dosage; Receptors, Purinergic P1 - metabolism; Theophylline; Theophylline - therapeutic use; Treatment Outcome; Vertebrates: nervous system and sense organs; Microwave; Memory impairment; Adenosine; Inhibitory avoidance task; Theophylline; Memory; Avoidance
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2006.10.059

Numerous studies have shown that acute microwave exposure causes cognitive deficits in animals, possibly via hyperthermia, but the biological effect of microwave exposure on memory processing is still unknown. The release of adenosine is demonstrated to be a general way for the cells to respond to metabolically stressful conditions such as hypoxia and ischemia. The present study aimed to examine whether adenosine mediates biological effects of microwave exposure on memory processing using a continuous multiple-trial inhibitory avoidance task. Results demonstrated that microwave exposure for 20 min before training impaired memory acquisition and retention performance in mice, assessed by the number of training trials and by latency to enter the dark compartment. The mice exposed to microwave radiation showed a dose-dependent hyperthermia. Moreover, the cell numbers of hippocampus were decreased in the mice receiving microwave exposure at an average power density of 50 mW/cm 2, indicating the anatomical correlation to hippocampal-amygdaloid structures corresponding with the memory disrupt of the mice. Administration of theophylline, a nonspecific adenosine receptor antagonist, 30 min before microwave exposure, completely antagonized the impairment of inhibitory avoidance acquisition but not retention. These results suggest that the adenosine regulation pathway was partially involved in microwave-induced impairment of inhibitory avoidance memory.