Effect of light deprivation on binding activity of serotonin with light and heavy synaptosomes from various brain formations.

The degree of binding of serotonin (5-HT) with light and heavy synaptosomes in various brain formations of control and visually deprived rabbits was studied by the writer's gel-filtration method. The activity of this process in heavy synaptosomes of control rabbits was equal in the visual cortex and superior colliculus and significantly higher than in the motor cortex. Light synaptosomes of all structures tested were similar in their degree of 5-HT binding. During light deprivation the intensity of this process in the heavy synaptosomes in formations of the visual system fell by 74-81%, whereas in the same synaptosomes of the motor cortex it fell by 31%. The decrease in 5-HT binding in the light synaptosomes of all formations tested was equal, mainly by about 73% of normal. The results are discussed in the light of the possible mediator or modulating role of 5-HT in formations of the visual system.