TY - JOUR
T1 - Regulation of corticotropin-releasing factor neuronal systems and hypothalamic-pituitary-adrenal axis activity by stress and chronic antidepressant treatment
AU - Stout, Steven C.
AU - Owens, Michael J.
AU - Nemeroff, Charles B.
PY - 2002
Y1 - 2002
N2 - In a series of experiments, we tested the hypothesis that chronic antidepressant drug administration reduces the synaptic availability of corticotropin-releasing factor (CRF) through one or more effects on CRF gene expression or peptide synthesis. We also determined whether effects of acute or chronic stress on CRF gene expression or peptide concentration are influenced by antidepressant drug treatment. Four-week treatment with venlafaxine, a dual serotonin (5-HT)/norepinephrine (NE) reuptake inhibitor, and tranylcypromine, a monoamine oxidase inhibitor, resulted in an attenuation of acute stress-induced increases in CRF heteronuclear RNA (hnRNA) synthesis in the paraventricular nucleus (PVN). Trends toward the same effect were observed after treatment with the 5-HT reuptake inhibitor fluoxetine, or the NE reuptake inhibitor reboxetine. CRF mRNA accumulation in the PVN during exposure to chronic variable stress was attenuated by concurrent antidepressant administration. Basal CRF hnRNA and mRNA expression were not affected by antidepressant treatment in the PVN or in other brain regions examined. Chronic stress reduced CRF concentrations in the median eminence, but there were no consistent effects of antidepressant drug treatment on CRF, serum corticotropin, or corticosterone concentrations. CRF receptor expression and basal and stress-stimulated HPA axis activity were unchanged after antidepressant administration. These results suggest that chronic antidepressant administration diminishes the sensitivity of CRF neurons to stress rather than alters their basal activity. Additional studies are required to elucidate the functional consequences and mechanisms of this interaction.
AB - In a series of experiments, we tested the hypothesis that chronic antidepressant drug administration reduces the synaptic availability of corticotropin-releasing factor (CRF) through one or more effects on CRF gene expression or peptide synthesis. We also determined whether effects of acute or chronic stress on CRF gene expression or peptide concentration are influenced by antidepressant drug treatment. Four-week treatment with venlafaxine, a dual serotonin (5-HT)/norepinephrine (NE) reuptake inhibitor, and tranylcypromine, a monoamine oxidase inhibitor, resulted in an attenuation of acute stress-induced increases in CRF heteronuclear RNA (hnRNA) synthesis in the paraventricular nucleus (PVN). Trends toward the same effect were observed after treatment with the 5-HT reuptake inhibitor fluoxetine, or the NE reuptake inhibitor reboxetine. CRF mRNA accumulation in the PVN during exposure to chronic variable stress was attenuated by concurrent antidepressant administration. Basal CRF hnRNA and mRNA expression were not affected by antidepressant treatment in the PVN or in other brain regions examined. Chronic stress reduced CRF concentrations in the median eminence, but there were no consistent effects of antidepressant drug treatment on CRF, serum corticotropin, or corticosterone concentrations. CRF receptor expression and basal and stress-stimulated HPA axis activity were unchanged after antidepressant administration. These results suggest that chronic antidepressant administration diminishes the sensitivity of CRF neurons to stress rather than alters their basal activity. Additional studies are required to elucidate the functional consequences and mechanisms of this interaction.
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U2 - 10.1124/jpet.300.3.1085
DO - 10.1124/jpet.300.3.1085
M3 - Article
C2 - 11861819
AN - SCOPUS:0036175309
VL - 300
SP - 1085
EP - 1092
JO - Journal of Pharmacology and Experimental Therapeutics
JF - Journal of Pharmacology and Experimental Therapeutics
SN - 0022-3565
IS - 3
ER -