Federal State Budgetary Institutions of Russian Academy of Medical Sciences:
1«Institute of general pathology and pathophysiology» and 2«Zakusov Institute of the Pharmacology». Moscow, Russia, E mail: email@example.com
The effect of hypoxia (10% O2) in the conditions of normal air pressure (760 mm Hg) on audiogenic seizures (AGS) caused by ultrasound (24.3kHz, 116dB) was studied. Ultrasound frequency of the radiation 24.3 kHz, with the level of sound 116 dB (completely silent for a person), can cause AGS up to 3÷9% of the rats. The work was carried out on 4 autbred white male rats, which were sampled as to their sensitivity to ultrasound. We determined latent periods of nervous excitement and moments of the onset of a seizure in seconds, as well as the intensity of the AGS according to 9-points scale. The action of ultrasound was carried out continuously and was turned off after the onset of a seizure. Note that for the exposure of rats under hypoxia conditions (10%O2, 760 mm Hg) we used the installation of the company of “Hypoxia Medical”. First, the experimental rats were influenced by ultrasound and the parameters of the AGS (control parameters) were defined. Then in 48 hours the rats were placed under hypoxia conditions (10%O2,) for 15 minutes and then right away the rats were subjected to the ultrasound; and we defined the parameters of the AGS for the second time (experimental parameters). And finally, after 24 hours the same rats were subjected to ultrasound and the AGS parameters were defined for third time. We compared AGS settings for 48 hours prior to the experience (control parameters), right after the experiment and 24 hours after the experiment. The results of the experiment showed that after 15 minutes of hypoxia (10%O2) influence the effect of hypoxic inhibition is observed in rats. The effect was manifested the reduction of the AGS intensity, increase in latent periods of motor stimulation by 60% and the onset of a seizure at by 90%, and also decrease of seizure intensity (severity) in 3 times. After 24 hours after the impact of hypoxia (10%O2) were measured AGS parameters in this same rat. They do not differ from the control parameters. The second group of rats served as a control. In the control rats after 15 minute «false exposure» in the conditions of normal oxygen content in the air (21%O2), any of the inhibition effect is not observed. The effect of the inhibition AGS under the influence of hypoxia (10%O2) indicates the possibility of the hypoxia therapy of epilepsy. In addition the inhibition effect, caused by hypoxia, can be used in itself as a test for the estimation of the combined action of hypoxia and pharmacological drug on the brain. In order to be confident in the work of the experimental model of epilepsy as a physiological marker we used antiepileptic drug carbamazepine.