Regulation of cerebral serotonin binding and metabolism in sleep-deprived rats

Two different binding sites are found for serotonin binding to crude membrane fractions isolated from rat brain. After 12 h sleep deprivation (SD) the dissociation constant of the high affinity binding KD1 = 1.4 mM, remains unchanged whereas the dissociation constant, KD2, of the low affinity binding increased from 26 to 42 nM. The number of binding sites are only moderately affected. The dissociation constant of the low affinity binding, KD2, is decreased towards control values if SD is followed by 1 or 4 h sleep. As indicated by serotonin and 5-hydroxyindoleacetic acid analyses, a statistically significant increase in serotonin metabolism is found only, if SD is followed by 1 h recovery sleep.