5-HT2C receptor involvement in female rat lordosis behavior.
Adult, hormone-primed, ovariectomized rats (CDF-344) with bilateral implants within the ventromedial nucleus of the hypothalamus (VMN), were injected with 0.5 microgram estradiol benzoate followed 48 h later with 500 microgram progesterone. This priming produced rats with 2 different levels of sexual receptivity. Rats with a lordosis to mount ratio (L/M)>/=0.5 were used to examine the potential lordosis-inhibiting effects of the 5-HT2A receptor antagonist, R(+)-a-(2, 3-dimethoxyphenyl)-1-[2(4-fluoro-phenylethyl)]-4-piperidine-methanol (MDL 100,907), and the 5-HT2C receptor antagonist, 5-methyl-1-(3-pyridylcarbamoyl)-1,2,3,5-tetrahydropyrrolo[2, 3-f]indole (SB 206553). Rats with low sexual receptivity (L/M<0.5) were bilaterally infused with the 5-HT2A/2C receptor agonist, (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane HCl (DOI), or DOI plus either MDL 100,907 or SB 206553 to determine if either drug would attenuate the lordosis-facilitating effects of DOI. The 5-HT2C receptor antagonist, but not the 5-HT2A receptor antagonist, effectively inhibited lordosis behavior. Similarly, SB 206553 was more effective than MDL 100,907 in reducing the DOI-induced increase in lordosis responding. However, both drugs limited the duration of lordosis responding initiated by DOI. These results are consistent with prior suggestions that 5-HT2A/2C receptors within the VMN are involved in the modulation of lordosis behavior and lead to the suggestion that 5-HT2C, rather than 5-HT2A, receptors are primarily responsible for the effects of 5-HT2 receptor-active drugs on lordosis behavior.
Wolf
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A
Department of Biology, Texas Woman's University, P.O. Box 425799, Denton, TX 76204-5799, USA.
Caldarola-Pastuszka
M
M
DeLashaw
M
M
Uphouse
L
L
D000818:Animals; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D005260:Female; D005464:Fluorobenzenes / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D007215:Indophenol / Q000031:analogs & derivatives / Q000494:pharmacology; D007650:Ketanserin / Q000494:pharmacology; D010052:Ovariectomy; D010880:Piperidines / Q000494:pharmacology; D011187:Posture; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D044405:Receptor, Serotonin, 5-HT2C; D011985:Receptors, Serotonin / Q000502:physiology*; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D012726:Sexual Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D014697:Ventromedial Hypothalamic Nucleus / Q000737:chemistry / Q000187:drug effects / Q000502:physiology*
D005464:Fluorobenzenes; D007211:Indoles; D010880:Piperidines; D011725:Pyridines; D044405:Receptor, Serotonin, 5-HT2C; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; C113896:dimethoxy-4-indophenyl-2-aminopropane; C074283:estradiol 3-benzoate; D004958:Estradiol; D007215:Indophenol; D007650:Ketanserin; C094868:SB 206553; C079049:volinanserin