Influence of Inosine on Cerebral Hemodynamics in Space Motion Sickness in Experimental Animals

Background: Motion sickness occurs worldwide in healthy individuals regardless of age, ethnicity, or gender. It is an acute disorder; it can also present as a chronic disorder in some individuals. Motion sickness not only includes vomiting and nausea, but also includes other features such as pallor of varying degrees, cold sweating, headache, drowsiness, increased salivation, and cranial pain, which are severe. Some of the other assessment scales can interpret sickness on exposure to virtual or visual stimulation and while travelling in different types of transport.

Aim: The aim of our research is to study the effect of the drug on the level of blood flow and vascular reactivity of cerebral vessels when simulating changes in the cerebral circulation in terrestrial conditions characteristic of hypogravity.

Methods: Chronic experiments were performed on non-anesthetized rabbits with large hemispheres, thalamus and hypothalamus were implanted with the needle-platinum electrodes 150 mm in diameter in the cortex, and local blood flow and vascular reactivity were recorded accordingly. Cerebrovascular disturbances were modeled using an MSAOP (motion sickness of animals in the anti-orthostatic position) with an inclined angle of 45° for 2 hours. Local blood flow (BF) was measured in ml/min/100g of tissue by the method of registration of hydrogen clearance. The vasodilator coefficient of reactivity (CrCO₂) was calculated by the ratio of BF against the background of inhalation of a mixture of 7% CO₂ with air to the initial BF; vasoconstrictor - in relation to BF on the background of inhalation of 100% O₂ to the initial BF (CrO₂). A series of experiments were carried out with different routes of drug administration: First, inosine was administered intravenously at a dose of 5 mg/kg immediately before the start of SMS modeling, same dose was administered 30 minutes before the start of exposure. As a control, we used the results of experimental animals under similar conditions without the administration of the drugs.

Results: Inosine has pronounced protective properties in cerebrovascular disorders on the background of space motion sickness (SMS) modeling, which is manifested by normalization of BF and restoration of compensatory reactions of cerebral vessels. In the mechanism of cerebroprotective action of inosine, it is able to correct the metabolic processes, which play an important role and help increase the compensatory capabilities and functional stability of the cerebrovascular system under gravitational influences.

Conclusion: When using inosine orally, the effects are more pronounced than when administered intravenously, which should be taken into account when using it for the prevention of cerebrovascular disorders in extreme conditions.