In the ventral tegmental area, progestins have actions at D1 receptors for lordosis of hamsters and rats that involve GABA A receptors.
In the ventral tegmental area (VTA), progestins facilitate lordosis via actions at gamma-aminobutyric acid (GABA)(A)/benzodiazepine receptor complexes (GBRs) and dopamine type 1 receptors (D1). The relationship between progestins' actions at GBRs and D1 in the VTA for facilitating sexual behavior of hamsters and rats was examined. Ovariectomized (ovx), estradiol (E(2); 10 microg)+progesterone (P; 250 microg; SC)-primed hamsters, with bilateral guide cannulae to the VTA, were pre-tested for sexual and motor behavior and infused with the GBR antagonist bicuculline (100 ng/side) or vehicle. Thirty minutes later, hamsters were re-tested and then infused with the D1 agonist SKF38393 (100 ng/side) or vehicle. Hamsters were post-tested 30 min later. Ovx, E(2) (10 microg)-primed rats were pre-tested, infused first with bicuculline or vehicle, second with SKF38393 or vehicle, third with 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP; 0, 100, or 200 ng) and were post-tested 10 and 60 min after 3alpha,5alpha-THP infusions. VTA infusions of SKF38393 increased lordosis of hamsters or rats. Bicuculline pretreatment reduced SKF38393- and/or progesterone-mediated increases in lordosis of E2-primed hamsters. In E2-primed rats, bicuculline blocked SKF38393- and/or 3alpha,5alpha-THP-mediated increases in lordosis. There were no effects on motor behavior. Thus, in the VTA, GBR activity modulates D1-mediated actions for lordosis of hamsters and rats.
Frye
Cheryl A
CA
Department of Psychology, The University at Albany-SUNY, Albany, NY 12222, USA. cafrye@albany.edu
Walf
Alicia A
AA
Petralia
Sandra M
SM
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D006224:Cricetinae; D003900:Desoxycorticosterone / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D018491:Dopamine Agonists / Q000008:administration & dosage / Q000494:pharmacology; D005260:Female; D018756:GABA Antagonists / Q000494:pharmacology; D007267:Injections; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D011187:Posture; D011372:Progestins / Q000494:pharmacology*; D051381:Rats; D020318:Rats, Long-Evans; D017447:Receptors, Dopamine D1 / Q000187:drug effects*; D011963:Receptors, GABA-A / Q000502:physiology*; D012726:Sexual Behavior, Animal / Q000187:drug effects*; D013045:Species Specificity; D013256:Steroids / Q000008:administration & dosage / Q000494:pharmacology; D017557:Ventral Tegmental Area / Q000187:drug effects / Q000502:physiology*
D018491:Dopamine Agonists; D018756:GABA Antagonists; D011372:Progestins; D017447:Receptors, Dopamine D1; D011963:Receptors, GABA-A; D013256:Steroids; D003900:Desoxycorticosterone; C009413:tetrahydrodeoxycorticosterone; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D001640:Bicuculline