Effects of highly or relatively selective 5-HT1A receptor agonists on lordosis in female rats.
To investigate the role of serotonin (5-HT) receptor 1A or 7 in regulating lordosis behavior in female rats, ovariectomized rats were treated with 3 kinds of receptor agonists and lordosis behavior was observed. The injected agents were the selective 5-HT1A receptor agonist, buspirone (BUS), the highly selective 5-HT1A receptor agonist, 8-hydroxy-2-(di-n-propylamino)tetralin ((+/-)8-OH-DPAT), and the 5-HT1A and 5-HT7 receptor agonist, (R)-8-hydroxy-2-(di-n-propylamino)tetralin ((+)8-OH-DPAT). A behavioral test was performed after ovariectomy and subcutaneous implantation of a silicon tube containing estradiol. Female rats in which the lordosis quotient (LQ) was over 70 were intraperitoneally injected with several doses of these agents. As a result, in the BUS group, the dose of 3 mg/kg bw, but not 1 mg/kg was effective for suppressing lordosis. On the other hand, an inhibitory effect was observed from 0.25 mg/kg and 0.5 mg/kg in the (+)8-OH-DPAT and (+/-)8-OH-DPAT groups, respectively. In the time-course experiment, in all drug-treated groups, LQ decreased to lower than 20 after 15 min and low LQ continued for 1 hr at least. Measurement of locomotor activity using an infrared sensor system showed no relation between the decrease in lordosis by these agents and spontaneous locomotion. These results indicate that 5-HT1A is strongly involved in the lordosis-inhibiting circuit of the serotonin neurons.
Laboratory of Neuroendocrinology, Department of Human Behavior and Environment Sciences, School of Human Sciences, Waseda University, Saitama, Japan.
Miki
M
Kishitake
Korehito
K
Yamanouchi
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000378:metabolism; D000818:Animals; D002065:Buspirone / Q000378:metabolism; D004958:Estradiol / Q000378:metabolism; D005260:Female; D009043:Motor Activity / Q000502:physiology; D011187:Posture / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D044282:Receptor, Serotonin, 5-HT1A / Q000378:metabolism / Q000502:physiology*; D058825:Serotonin 5-HT1 Receptor Agonists; D012726:Sexual Behavior, Animal / Q000502:physiology*
D058825:Serotonin 5-HT1 Receptor Agonists; D044282:Receptor, Serotonin, 5-HT1A; D004958:Estradiol; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D002065:Buspirone