[The influence of adenosine receptor ligands and hypoxic preconditioning on the metabolism of the brain tissue in the experiment].

Aim: To study the influence of adenosine receptor ligands and hypoxic preconditioning on carbohydrate metabolism in global brain ischemia.

Material And Methods: The study included 51 outbred white male mice weighing 20-25 g. An effect of adenosine receptor ligands and hypoxic preconditioning on brain tissue metabolism, heat exchange and longevity was explored.

[Importance of selective A1 agonists for the protection of brain and heart against injuring factors].

Powerful selective A1 agonist N6-cyclopentyladenosine (CPA) effectively protects the brain (upon decapitation) and the heart (upon intoxication by KCl or ethylen glycol tetra acetate (EGTA)) against the action of injuring factors on experimental animals. CPA weakens or removes damages and/or cell death and probably promotes the regeneration of tissue structures and restoration of their functions. Thus, CPA increases the tolerance of the heart and brain with respect to the introduction of two strong toxicants and even upon decapitation.

[Different types of hypoxic preconditioning protect the brain against complete global ischemia].

Different types of hypoxia, including several new models, protect the brain against complete global ischemia. Hypoxic (stay in hermetic chamber without or with consumption of CO2 and H2O exhaled), circulatory (bleeding), hematic (injections of NaNO2, CoCl2, NiCl2) and tissue (histotoxic) hypoxia (K2-malonate injection) increases cerebral ischemic tolerance in early terms (in hours). Intracerebroventricular injections of NaNO2, CoCl2, NiCl2 and K2-malonate in nontoxic doses have weak effects.

[New approaches to brain protection against global ischemia].

Three pathways to increase tolerance to global cerebral ischemia have been worked out: (1) the use of inhibitory neurotransmitters and their analogues; (2) injection of neuroleptics; (3) hypoxic preconditioning. We revealed the importance of receptors, K(ATP) channels and induction of hypothermia in neuroprotective mechanisms of these influences.

[The role of hypothermia in brain protection by adenosine receptor agonists].

Agonists of A1 adenosine receptors induce a profound hypothermia that is correlated with a considerable increase in tolerance with respect to the global cerebral ischemia. Thermal irradiation of the head considerably decreases and the thermoneutral temperature completely prevents (i) the development of hypothermia in the body and, especially, in the cortex and (ii) the neuroprotection, so that a correlation of these two effects disappears. The induction of hypothermia is the most important but not single mechanism of neuroprotective action of A1-receptor agonists.