| Abstract: | —Rats were reared in complete darkness or under chronic stimulation with flashing light from birth to the age of 7 weeks. Light deprivation caused a significant increase in monoamine oxidase activity (measured with 14C]serotonin) of about 30 per cent in the structures of the visual pathway. Chronic stimulation with flashing light had no influence on the activity of monoamine oxidase in either visual or non-visual structures. The activity of catechol-O-methyl transferase in the brain areas of light-deprived rats was reduced, in light-stimulated rats it was slightly increased. In mother rats kept together with their litters in either complete darkness or flashing light for 5 weeks no change in monoamine oxidase activity was observed. The activity of catechol-O-methyl transferase in mother rats kept in darkness was significantly decreased in all brain regions studied; in light-stimulated animals the enzyme activity was not affected. |
