title: Microinjection of the preferential dopamine receptor D3 agonist 7-hydroxy-N,N-di-n-propylaminotetralin hydrobromide into the hypothalamic medial preoptic area induced ejaculation in anesthetized rats.
abstract: The pivotal role of the medial preoptic area (MPOA) of the hypothalamus in the dopaminergic cerebral control of ejaculation has been investigated for years; nevertheless the function of different dopamine receptors subclasses and their exact interrelations merit additional research. One hundred nanograms of a preferential D(3) agonist 7-OH-DPAT (7-hydroxy-N,N-di-n-propylaminotetralin hydrobromide) was microinjected unilaterally into the MPOA of male rats anesthetized with urethane. An ejaculation-related response (bulbospongiosus muscles rhythmic contractions and/or seminal vesicle pressure increases and/or expulsion of a semen plug) was observed in 8 of 10 rats devoid of sexual stimuli, while a similar response was observed in only one rat administered with 10 ng of 7-OH-DPAT. The effect of 7-OH-DPAT 100 ng was mostly abolished by simultaneous MPOA microinjection of 300 ng of a preferential D(3) antagonist N-[(n-butyl-2-pyrrolidinyl) methyl]-1-methoxy-4-cyanonaphthalene-2-carboxamide tartrate (nafadotride). Our results support the hypothesis that supraspinal command of ejaculation is mediated by D(2)-like receptors, probably by D(3) receptors, in the MPOA, and draw attention to the idea of these receptors serving as a promising target for pharmacological treatment of human ejaculatory disorders.
authors.affiliation: Department of Urology, Chaim Sheba Medical Center, Tel-Hashomer, 52621 Ramat-Gan, Israel.
authors.forename: N D
authors.initials: ND
authors.lastname: Kitrey
authors.forename: P
authors.initials: P
authors.lastname: Clément
authors.forename: J
authors.initials: J
authors.lastname: Bernabé
authors.forename: L
authors.initials: L
authors.lastname: Alexandre
authors.forename: F
authors.initials: F
authors.lastname: Giuliano
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004542:Ejaculation / Q000187:drug effects*; D004576:Electromyography; D008297:Male; D008845:Microinjections; D009281:Naphthalenes / Q000494:pharmacology; D011301:Preoptic Area / Q000502:physiology*; D011759:Pyrrolidines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D050637:Receptors, Dopamine D3 / Q000819:agonists* / Q000037:antagonists & inhibitors; D013764:Tetrahydronaphthalenes / Q000494:pharmacology*
chemical_list: D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D009281:Naphthalenes; D011759:Pyrrolidines; D050637:Receptors, Dopamine D3; D013764:Tetrahydronaphthalenes; C097285:nafadotride; C031349:7-hydroxy-2-N,N-dipropylaminotetralin