Effects of 5-HT1 and 5-HT 2 Receptor Agonists on Electromagnetic Field-Induced Analgesia in Rats.

Much evidence demonstrates the antinociceptive effect of magnetic fields (MFs). However, the analgesic action mechanism of the electromagnetic field (EMF) is not exactly understood. The aim of the present study was to investigate the effects of 5-HT1 and 5-HT2 receptor agonists (serotonin HCl and 2,5-dimethoxy-4-iodoamphetamine [DOI] hydrochloride) on EMF-induced analgesia. In total, 66 adult male Wistar albino rats with an average body mass of 225 ± 13 g were used in this study. The animals were subjected to repeated exposures of alternating 50 Hz and 5 mT EMF for 2 h a day for 15 days. Prior to analgesia tests, serotonin HCl (5-HT1 agonist) 4 mg/kg, WAY 100635 (5-HT1 antagonist) 0.04 mg/kg, DOI hydrochloride (5-HT2 receptor agonist) 4 mg/kg, and SB 204741 (5-HT2 antagonist) 0.5 mg/kg doses were injected into rats. For statistical analysis of the data, analysis of variance was used and multiple comparisons were determined by Tukey's test. Administration of serotonin HCl MF (5 mT)-exposed rats produced a significant increase in percent maximal possible effect (% MPE) as compared with EMF group (P < 0.05). On the contrary, injection of WAY 100635 to MF-exposed rats produced a significant decrease in analgesic activity (P < 0.05). Similarly, the administration of DOI hydrochloride significantly increased % MPE values as compared with the EMF group while SB 204741 reduced it (P < 0.05). In conclusion, our results suggested that serotonin 5-HT1 and 5-HT2 receptors play an important role in EMF-induced analgesia; however, further research studies are necessary to understand the mechanism. Bioelectromagnetics. 2019;40:319-330. © 2019 Bioelectromagnetics Society.

Serum selenium and plasma malondialdehyde levels and antioxidant enzyme activities in patients with obsessive-compulsive disorder.

There is mounting evidence indicating that reactive free radical species are involved in initiation and development of many different forms of human pathologies including psychiatric disorders. In the present study, we aimed to determine whether serum selenium (Se), antioxidant enzyme (glutathione peroxidase, GSH-Px, superoxide dismutase, SOD, and catalase, CAT) activities, and plasma malondialdehyde (MDA) levels, a product of lipid peroxidation, were associated with obsessive-compulsive disorder (OCD). The participants were 28 patients with OCD that were drug-free at least for a month and a control group (n=28) of healthy subjects, matched with respect to age and sex. In both groups, the levels of the erythrocyte MDA, GSH-Px, SOD, Se, and the CAT were measured. The levels of MDA and SOD were statistically significantly higher (p<0.01, p<0.05 respectively) in patients than controls. The activities of CAT, GSH-Px, and serum Se levels were statistically significantly lower (p<0.0001, p<0.001, and p<0.001 respectively) in patients than controls. There was a positive correlation in patients between plasma GSH-Px activity and Se concentration (r=52, p=0.001). However, in patients with OCD, CAT and SOD activities were significantly and negatively correlated with MDA levels (r=-0.45, p=0.017 for CAT and r=-0.54, p=0.020 for SOD). The study shows the presence of a significant relationship of OCD and oxidative stress, and consequently, an involvement of free radicals and of the antioxidant defence.