Soy and social stress affect serotonin neurotransmission in primates.
Stress and sex steroidal milieu can each influence mood in women. The purpose of this study was to compare the effect of long-term conjugated equine estrogen (CEE), soy phytoestrogen (SPE), and social subordination stress on dorsal raphe serotonin neurotransmission of ovariectomized cynomolgus monkeys. Tryptophan hydroxylase (TPH) and serotonin reuptake transporter (SERT) protein content were determined, and the in vitro degradation of macaque SERT protein was examined in the presence and absence of protease inhibitors, serotonin (5-HT), and citalopram. Like CEE, SPE increased TPH protein levels. Social subordinates had markedly lower TPH protein levels than dominants regardless of hormone replacement. Therefore, these two variables had independent and additive effects. CEE and SPE increased SERT, and social status had no effect. Thus, the hormone-induced increase in SERT was accompanied by increased 5-HT synthesis and neuronal firing, which appears biologically reasonable as 5-HT prevented SERT degradation in vitro.
Department of Pathology, Section of Comparative Medicine, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, NC 27157, USA. cshively@wfubmc.edu
C A
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Shively
S J
SJ
Mirkes
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Lu
J A
JA
Henderson
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CL
Bethea
D000818:Animals; D015153:Blotting, Western; D001923:Brain Chemistry / Q000187:drug effects; D002352:Carrier Proteins / Q000378:metabolism; D015283:Citalopram / Q000494:pharmacology; D003720:Densitometry; D004291:Dominance-Subordination; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D007529:Isoflavones / Q000494:pharmacology*; D008252:Macaca fascicularis; D008562:Membrane Glycoproteins / Q000378:metabolism; D026901:Membrane Transport Proteins; D008636:Mesencephalon / Q000737:chemistry / Q000378:metabolism; D009419:Nerve Tissue Proteins; D010052:Ovariectomy; D048789:Phytoestrogens; D010870:Pineal Gland / Q000378:metabolism; D028321:Plant Preparations / Q000494:pharmacology*; D011480:Protease Inhibitors / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology / Q000502:physiology*; D050486:Serotonin Plasma Membrane Transport Proteins; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology; D012931:Social Environment; D013025:Glycine max; D013315:Stress, Psychological / Q000503:physiopathology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D002352:Carrier Proteins; D015283:Citalopram; D004967:Estrogens; D007529:Isoflavones; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D048789:Phytoestrogens; D028321:Plant Preparations; D011480:Protease Inhibitors; D012701:Serotonin; D050486:Serotonin Plasma Membrane Transport Proteins; D017367:Selective Serotonin Reuptake Inhibitors; D014446:Tyrosine 3-Monooxygenase