Serotonin-2 binding sites in human frontal cortex and hippocampus. Selective loss of S-2A sites with age.
Serotonin (S-2) binding sites were characterized in human frontal cortex and hippocampus throughout the lifespan. We found that the S-2 binding sites (labeled by [3H]spiperone and displaced by ketanserin) consisted of two subtypes (S-2A and S-2B) which are discriminated by competition with methysergide. The total S-2 sites in frontal cortex had a Bmax of 360 fmol/mg protein, which is approximately twice that of the hippocampus (160 fmol/mg protein). The density of total S-2 sites decreased with age in the frontal cortex of normal adults (17-100 years, n = 24). The receptor loss was primarily in the S-2A subclass. This loss of S-2A sites occurred primarily after 60 years and decreased to 50% of young adult values by the 10th decade. In the hippocampus, S-2A binding sites decreased with age, but no effects on total S-2 or S-2B sites were detected. A study of infant brains suggested the S-2A subtype in frontal cortex increases postnatally. However, in the infant hippocampus the S-2 binding approximated adult levels.
D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging; D002540:Cerebral Cortex / Q000254:growth & development* / Q000378:metabolism; D006624:Hippocampus / Q000254:growth & development* / Q000378:metabolism; D006801:Humans; D007650:Ketanserin; D007700:Kinetics; D008784:Methysergide / Q000494:pharmacology; D008875:Middle Aged; D009928:Organ Specificity; D010880:Piperidines / Q000494:pharmacology; D011985:Receptors, Serotonin / Q000187:drug effects / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism*; D012702:Serotonin Antagonists / Q000494:pharmacology; D013134:Spiperone / Q000378:metabolism
D010880:Piperidines; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D012701:Serotonin; D013134:Spiperone; D007650:Ketanserin; D008784:Methysergide