Serotonin receptor subtypes in depression: evidence from studies in neuroendocrine regulation.
Serotonin (5-HT) neuroendocrine tests are a valid and acceptable means of measuring 5-HT neurotransmission in humans. Recently, the availability of selective 5-HT receptor ligands has allowed the assessment of specific 5-HT receptor subtype function using neuroendocrine methods. Studies with selective antagonists have shown that the endocrine responses to the 5-HT precursor L-tryptophan (LTP) are mediated via postsynaptic 5-HT1A receptors, whereas endocrine responses produced by the 5-HT-releasing agent d-fenfluramine involve postsynaptic 5-HT2/1C receptors. Endocrine responses to both LTP and fenfluramine are consistently decreased in depressive illness. In contrast, endocrine responses to direct 5-HT1A and 5-HT2/1C receptor agonists are not consistently attenuated in depressed patients. The current data suggest that depressive illness is associated with an impairment of 5-HT neurotransmission that involves decreased 5-HT release rather than altered sensitivity of postsynaptic 5-HT receptors.
Cowen
P J
PJ
MRC Unit of Clinical Pharmacology, Littlemore Hospital, Oxford, England.
D003863:Depression / Q000188:drug therapy / Q000503:physiopathology*; D006801:Humans; D009490:Neurosecretory Systems / Q000502:physiology*; D011985:Receptors, Serotonin / Q000145:classification* / Q000502:physiology*; D012701:Serotonin / Q000502:physiology*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology
D011985:Receptors, Serotonin; D012701:Serotonin; D017366:Serotonin Receptor Agonists; D017367:Selective Serotonin Reuptake Inhibitors