Estrogen receptor (ER) subtype agonists alter monoamine levels in the female rat brain.
We assessed the effects of subtype-selective ER agonists on monoamine levels in discrete regions of the female rat brain. Ovariectomized (ovx) rats were treated for 4 days with vehicle, 17β-estradiol (E; 0.05mg/kg), an ERβ agonist (C19; 3mg/kg) or an ERα agonist (PPT; 3mg/kg) and samples from brain regions were assessed for monoamines and metabolites. We also assessed effects of ERβ modulation on baseline and fenfluramine-induced release of monoamines in hippocampus using microdialysis. In the first study, E and the ERα agonist increased norepinephrine in cortex and all three ER ligands increased it in the ventral hippocampus. Changes in levels of the noradrenergic metabolite, MHPG and the dopaminergic metabolite, DOPAC were noted in brain areas of ER ligand-treated animals. E also increased levels of 5HIAA in three brain areas. In the microdialysis study, there were no differences among groups in baseline levels of monoamines. However, E and the ERβ agonist increased levels of the dopaminergic metabolite, HVA following fenfluramine. In summary, activation of the two nuclear ERs with selective agonists affects monoamine and metabolite levels in discrete brain areas, a number of which are known to play key roles in cognitive and affective function.
Lubbers
Laura S
LS
Department of Pharmacology, Merck Research Laboratories, Rahway, NJ 07065, USA. Laura_Lubbers@merck.com
Zafian
Peter T
PT
Gautreaux
Claris
C
Gordon
Marisa
M
Alves
Stephen E
SE
Correa
Lucia
L
Lorrain
Daniel S
DS
Hickey
Gerard J
GJ
Luine
Victoria
V
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D015306:Biogenic Monoamines / Q000378:metabolism*; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology*; D047628:Estrogen Receptor alpha / Q000819:agonists; D047629:Estrogen Receptor beta / Q000819:agonists; D005260:Female; D005277:Fenfluramine / Q000494:pharmacology; D005449:Fluorenes / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D008734:Methoxyhydroxyphenylglycol / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism; D010052:Ovariectomy; D010636:Phenols / Q000494:pharmacology*; D011720:Pyrazoles / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011960:Receptors, Estrogen / Q000819:agonists*
C545987:4-bromo-9a-butyl-7-hydroxy-1,2,9,9a-tetrahydro-3H-fluoren-3-one; D015306:Biogenic Monoamines; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D005449:Fluorenes; D010636:Phenols; D011720:Pyrazoles; D011960:Receptors, Estrogen; C486184:4,4',4''-(4-propyl-((1)H)-pyrazole-1,3,5-triyl) tris-phenol; D015102:3,4-Dihydroxyphenylacetic Acid; D005277:Fenfluramine; D004958:Estradiol; D008734:Methoxyhydroxyphenylglycol; D006897:Hydroxyindoleacetic Acid; D009638:Norepinephrine