The Time Profile of the Effects of Moderate Hypothermia on Synaptic Acetylcholinesterase in Rat Brain.

Hypothermia in homeotherms significantly affects the neurotransmitter systems of the brain, including the cholinergic system. The function of the brain cholinergic system during prolonged moderate hypothermia is not known yet. We studied the effects of moderate hypothermia of various durations on the activity and kinetic parameters of synaptic acetylcholinesterase in rat brain.

Antioxidant Status of Rat Liver Mitochondria under Conditions of Moderate Hypothermia of Different Duration.

For evaluation of the contribution of the antioxidant system of mitochondria into the dynamics of changes in the prooxidant status, the content and activity of some of its components were studied under conditions of moderate hypothermia of varying duration. It was found that short-term hypothermia significantly increased superoxide dismutase activity and decreased the levels of low-molecular-weight antioxidants. Increasing the duration of hypothermia to 1 h led to suppression of activities of superoxide dismutase, glutathione reductase, and glutathione peroxidase and a decrease in glutathione content.

Respiratory Characteristics of Rat Liver Mitochondria Depend on the Duration of Moderate Hypothermia.

The development of pathological or compensatory-and-adaptive reactions in homoeothermic animals during various periods of hypothermia can be caused by shifts in the respiratory functions of the mitochondria. Short-term hypothermia promoted an increase in the rates of the glutamate- and succinate-dependent respiration of mitochondria. Phosphorylation rate increased as well, while oxidative phosphorylation coefficient (P/O), respiratory control, and 2,4-DNP sensitivity depended.

Thermostability of Lactate Dehydrogenase in Rat Brain under Conditions of Short-Term Moderate Hypothermia.

Thermostability of rat brain lactate dehydrogenase (LDH) was studied in intact animals and animals subjected to moderate short-term hypothermia. Two exponential stages, rapid and slow, were distinguished in the thermodenaturation kinetics. The contribution of the rapid phase to the lactate dehydrogenase denaturation kinetics was more significant: the energy of activation for this phase was 2.

A New Tellurium- and Selenoorganic Compound as an Inhibitor of Acetylcholinesterase in Brain.

We studied the effect of a new cyanine dye containing selenium and tellurium on acetylcholinesterase activity in synaptic membrane in rat brain. The cyanine dye dose-dependently inhibits activity of this enzyme, and the concentration of half-maximal inhibition of acetylcholinesterase activity was 20.46 μM.