Db. Parfitt et Sw. Newman, FOS-IMMUNOREACTIVITY WITHIN THE EXTENDED AMYGDALA IS CORRELATED WITH THE ONSET OF SEXUAL SATIETY, Hormones and behavior (Print), 34(1), 1998, pp. 17-29
We hypothesized that c-fos expression in the medial amygdala (Me), the
bed nucleus of the stria terminalis (BNST), and the medial preoptic a
rea (MPOA) of the male Syrian hamster brain correlated with sexual sat
iety. To address this hypothesis, males were mated for 4 consecutive d
ays. Experiment 1 determined whether the number of Fos-immunoreactive
(Fos-ir) nuclei was equivalent in two groups of males mated to sexual
satiety, one group of rested males (9.67 +/- 0.80 ejaculations) and a
second group mated for 4 consecutive days (3.50 +/- 0.56 ejaculations)
. Fos-ir was increased within the caudal posterodorsal Me (cMePD), the
anterodorsal and posteroventral subdivisions of the posteromedial BNS
T [BNSTpm(ad) and BNSTpm(pv)], the dorsolateral MPOA, and the medial p
reoptic nucleus of all males mated to sexual satiety compared to nonma
ted controls. In addition, Fos-ir ''clusters'' within the cMePD and BN
STpm(ad) were present in males mated to satiety regardless of the numb
er of ejaculations. However, all males achieved multiple ejaculations.
Therefore, Experiment 2 examined whether two groups of males stopped
at one ejaculation exhibit different patterns of Fos-ir depending on p
roximity to sexual satiety. Brains of consecutively mated males, close
r to satiety than rested males, showed greater BNSTpm(pv) Fos-ir and 5
/6 mates, but no rested male, exhibited cMePD Fos-ir clusters. These r
esults support the hypothesis that cMePD and BNSTpm(pv) neuronal activ
ation is associated with satiety and may constitute a discrete circuit
to terminate mating. (C) 1998 Academic Press.