Effects of 5-HT1A-Receptor Agonist, 8-OH-DPAT, and GABAB-Receptor Agonist, Baclofen, on Lordosis in Female Rats With Lesions in Either the Dorsal Raphe Nucleus or Septum

Abstract

Abstract. The inhibitory effects of 8-OH-DPAT, a 5-HT 1A -receptor agonist, and baclofen, a GABA B -receptor agonist, on lordosis were examined in estrogen and progesterone-treated ovariectomized rats with lesions in either the dorsal raphe nucleus (DRN) or septum and in rats with either sham lesions or no lesions. The first behavior test series was carried out 6 days after implantation of the rats with silicon tubes containing estradiol. Four hours after injection with 0.5 mg progesterone, behavioral tests were performed before and 30 min after an injection with 1 mg/ kg body weight 8-OH-DPAT. As a result, the mean lordosis quotient (LQ)s were changed from 100 to less than 20 before and after the injection in all groups. These results suggest that 8-OH-DPAT acts on areas other than the DRN and the septum, leading to a decrease in lordosis. Two weeks after implantation with estradiol, the next behavioral test series was carried out after injection with progesterone. Behavioral tests were performed before and after an injection with 10 mg baclofen. The results showed that the mean LQs decreased after the injection in all groups, but the mean LQ in the DRN lesion group was higher than that in the sham groups. These results indicate that baclofen may act partially on the DRN in inhibiting lordosis in female rats.

Sexual Dysfunction Associated With Intrathecal Baclofen Use: A Report of Two Cases

“…There have been no case reports to our knowledge on the effects of ITB on sexual function in women; however, researchers have noted an inhibitory effect of GABA in regulating sexual behavior in female rats (8). In female rats with dorsal raphe nucleus lesions, baclofen decreased lordotic (sexual) behavior, suggesting that GABA B receptors may be involved in the inhibitory mechanism regulating sexual behaviors (8).…”

“…In female rats with dorsal raphe nucleus lesions, baclofen decreased lordotic (sexual) behavior, suggesting that GABA B receptors may be involved in the inhibitory mechanism regulating sexual behaviors (8). This is an issue that will need further research and inquiry as more ITB pumps are placed in women.…”

Alteration of 5-Hiaa Levels in Frontal Cortex and Dorsal Raphe Nucleus in Rats Treated With Combined Administration of Tryptophan and Ethanol

“…In the first one, we examined alterations in 5-HT and its metabolite, 5-hydroxyindoleacetic acid (5-HIAA), in both the dorsal raphe nucleus and the frontal cortex after acute coadministration of tryptophan plus ethanol to rats. In the second one, we investigated how WAY100635 (10 μM), 5-HT 1A antagonist, or 8-OH-DPAT (10 μM), 5-HT 1A agonist perfused into the frontal cortex or the dorsal raphe nucleus after coadministration influences 5-H T releas e in both areas (Routledge et al, 1995;Kishitake and Yamanouchi, 2005). In addition, there are findings that the cerebral 5-HT system is associated with anxiety-related behavior (Gonzalez et al, 2000;Langen et al, 2002).…”