Effects of the dopamine D3 receptor ligand 7-OH-DPAT on male rat ejaculatory behavior.

As previously shown, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) produces a marked and highly characteristic facilitation of male rat ejaculatory behavior, and this effect is not sensitive to dopamine (DA) receptor antagonists of the D1 or D2 receptor families. The structural congener 7-OH-DPAT, primarily characterized as a DA D3 receptor selective ligand, produced a facilitation of male rat ejaculatory behavior, as evidenced by a dose-dependent decrease in the number of intromissions preceding ejaculation and in time to ejaculation. These effects could be antagonized by pretreatment with the DA D2/D3 receptor antagonist, raclopride. Thus, 7-OH-DPAT-induced effects on male rat ejaculatory behavior can be pharmacologically differentiated from effects produced by 8-OH-DPAT.