Abstract |
Previous studies showed that repeated estrogen treatment reduces the ability of the 5-HT(1A) receptor agonist, 8-hydroxy-2(di-n-propylamino) tetralin (8-OH-DPAT), to inhibit lordosis behavior of female rats. The present study evaluated the effects of repeated estrogen treatment on lordosis behavior and 5-HT(1A) receptor binding and coupling to G protein in the hypothalamus-preoptic area using the agonist ligand [3H]-8- OH-DPAT, which binds selectively to G-protein-coupled 5-HT(1A) receptors. Rats were injected twice with 25 or 50 microg of estradiol benzoate (EB) 7 days apart followed by 500 microg of progesterone (P) 48 h after the second EB injection. Controls received a single injection of 25 or 50 microg EB followed 48 h later by 500 microg of P. Four hours after P, 0.15 mg/kg 8-OH-DPAT was injected, and lordosis behavior examined for 30 min. Rats treated twice with EB showed significantly less 8-OH-DPAT inhibition of lordosis behavior than rats receiving a single EB injection. For receptor binding, rats received EB without P treatment. None of the estrogen treatments reduced [3H]-8- OH-DPAT binding density or affinity in the hypothalamus-preoptic area or hippocampus. These studies suggest that estrogen modulates 5-HT(1A) agonist potency without a measurable change in 5-HT(1A) receptor density or coupling to G protein.
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Authors | A Jackson, A M Etgen |
Journal | Pharmacology, biochemistry, and behavior
(Pharmacol Biochem Behav)
Vol. 68
Issue 2
Pg. 221-7
(Feb 2001)
ISSN: 0091-3057 [Print] United States |
PMID | 11267626
(Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)
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Chemical References |
- Receptors, Serotonin
- Receptors, Serotonin, 5-HT1
- estradiol 3-benzoate
- Progesterone
- Estradiol
- 8-Hydroxy-2-(di-n-propylamino)tetralin
- GTP-Binding Proteins
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Topics |
- 8-Hydroxy-2-(di-n-propylamino)tetralin
(metabolism, pharmacology)
- Animals
- Estradiol
(analogs & derivatives, pharmacology)
- Female
- GTP-Binding Proteins
(drug effects, metabolism)
- Hippocampus
(drug effects, metabolism)
- Posture
(physiology)
- Preoptic Area
(drug effects, metabolism)
- Progesterone
(pharmacology)
- Rats
- Rats, Sprague-Dawley
- Receptors, Serotonin
(drug effects, metabolism)
- Receptors, Serotonin, 5-HT1
- Sexual Behavior, Animal
(drug effects, physiology)
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