Appetitive and consummatory sexual behaviors of female rats in bilevel chambers II. Patterns of estrus termination following vaginocervical stimulation
Jg. Pfaus et al., Appetitive and consummatory sexual behaviors of female rats in bilevel chambers II. Patterns of estrus termination following vaginocervical stimulation, HORMONE BEH, 37(1), 2000, pp. 96-107
Copulation with intromission or manual vaginocervical stimulation (VCS) sho
rtens the duration that intact female rats maintain lordosis responding dur
ing estrus. The present study examined whether VCS could shorten the durati
on of both appetitive and consummatory measures of female sexual behavior,
and whether these effects occur differentially in time and across different
hormone priming intervals. Ovariectomized, sexually experienced female rat
s were administered subcutaneous injections of estradiol benzoate 48 h and
progesterone 4 h, before receiving 50 manual VCSs with a lubricated glass r
od distributed over 1 h. Control females received sham VCSs distributed ove
r the same time. The females were then tested for sexual behavior in bileve
l chambers with two sexually vigorous males (to one ejaculatory series or 1
0 min with each male, separated by 5 min) 12, 16, and 20 h after VCS. Prior
to the final hormone treatment, different groups of females had been given
the same hormone treatment either 28, 14, 7, or 4 days before. In females
tested at 28- and 14-day hormone intervals, VCS induced both active and pas
sive rejection responses at 12, 16, and 20 h. In contrast, females that rec
eived sham VCS displayed relatively normal sexual behavior at 12 h, althoug
h by 16 and 20 h these females displayed active and passive rejection. Fema
les tested at 7- or 4-day intervals displayed normal levels of lordosis at
all testing times, regardless of VCS treatment. These data indicate that VC
S facilitates rejection responses that precede the decrease in lordosis res
ponsiveness. However, the effects of VCS are dependent on the frequency of
hormone priming, suggesting that hormone treatment may block some of the lo
ng-term inhibitory effects of VCS on female sexual behavior. (C) 2000 Acade
mic Press.