Open AccessPlasma prolactin concentrations and copulatory behavior after salsolinol injection in male rats
Author(s) -
Terada Misao,
Oláh Mark,
Nagy György M.,
Taniguchi Kazumi,
Sato Fumio,
Muranaka Shiro,
Fungfuang Wirasak,
Kromkhun Pudcharaporn,
Nakada Tomoaki,
Yokosuka Makoto,
Saito Toru R.
Publication year - 2010
Publication title -
reproductive medicine and biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.005
H-Index - 22
eISSN - 1447-0578
pISSN - 1445-5781
DOI - 10.1007/s12522-010-0060-7
Subject(s) - medicine , endocrinology , prolactin , endogeny , estrous cycle , dopamine , sexual behavior , biology , chemistry , hormone , clinical psychology
Purpose The dopamine‐derived endogenous compound, R‐salsolinol (SAL), was recently identified as a putative endogenous prolactin (PRL)‐releasing factor. However, how SAL influences copulatory behavior is unknown. In this study, we examined the relationship between SAL and copulatory behavior in male rats. Methods Male Sprague‐Dawley rats administered SAL were exposed to female rats in estrus, the plasma PRL concentration was measured, and the behavioral frequency and time during copulatory behavior were noted. Results In the control and SAL groups, plasma PRL concentrations at 15 min before exposure to the female were 7.3 ± 2.0 and 8.0 ± 1.5 ng/ml, respectively. Moreover, plasma PRL concentrations in males immediately after exposure to the female were 7.4 ± 1.2 and 68.0 ± 5.9 ng/ml, respectively ( P < 0.05). All (8/8) of the control animals ejaculated in the presence of the female, whereas only 33% (2/6) of the SAL group ejaculated. An increasing tendency for mount latency and intromission latency and a decreasing tendency for intromission frequency were observed in the SAL group. Conclusions Copulatory behavior was inhibited in male rats after SAL injection, suggesting that SAL is a copulatory behavior inhibiting factor.