[Effect of prolonged cold exposure on monoamine oxidase activity and kinetics and on serotonin metabolism in the rat brain].

Effects of long-term cold exposure on the content of serotonin and its metabolite 5-hydroxyindolacetic acid (5-HIAA) and monoamine oxidase (MAO) activity and kinetic parameters (Km and Vmax) of oxidative deamination of serotonin in rat brain stem. The increase of 5-HIAA level in the initial period of chronic cold exposure was determined by the blockade of active metabolite transport from the brain. The level of serotonin and the rate of its catalytic deamination by MAO were found to be decreased in cold-adapted rats. The magnitude of the Km of serotonin deamination was unchanged.