Clonidine inhibits female spawning behavior in ovulated and prostaglandin-treated goldfish.

Previous studies have indicated that female spawning behavior in goldfish is stimulated by prostaglandin (PG) synthesized in the reproductive tract shortly after ovulation and acting within the brain. In this study, clonidine inhibited PG-induced spawning behavior of nonovulated female goldfish in a dose-dependent manner and also inhibited spawning of ovulated goldfish. In male goldfish, clonidine also inhibited PG-induced female spawning behavior but did not affect male spawning behavior. The results provide further support for a role of endogenous PG in female spawning behavior of goldfish and are consistent with the findings [15] that clonidine antagonizes the action of PG on sexual behavior in the female guinea pig.