Progestin facilitation of lordosis in rodents involves adenylyl cyclase activity in the ventral tegmental area

Horm Behav. 2006 Aug;50(2):237-44. doi: 10.1016/j.yhbeh.2006.03.006. Epub 2006 Apr 27.

Abstract

Increasing cAMP, or activating dopamine type 1 (D(1)) or GABA(A)/benzodiazepine receptor complexes (GBRs), in the ventral tegmental area (VTA) enhances lordosis of rodents. Whether D(1)- and/or GBR-mediated increases in progestin-facilitated lordosis involve the cAMP-synthesizing enzyme, adenylyl cyclase, in the VTA, was investigated. In Experiment 1, ovariectomized estradiol (E(2); 10 microg at h 0)+progesterone (P; 250 microg at h 45)-primed hamsters first received bilateral infusions of the adenylyl cyclase inhibitor, 2',5'-dideoxyadenosine (DDA; 12 microM/side), or vehicle, and then were infused with the D(1) agonist, SKF38393 (100 ng/side), the GBR agonist, muscimol (100 ng/side), or vehicle, to the VTA. Lordosis was evaluated before and 30 min after each infusion. In Experiment 2, ovariectomized, E(2)-primed (10 microg at h 0) rats received VTA infusions of DDA (12 microM/side) or vehicle; SKF38393 (100 ng/side), muscimol (100 ng/side), or vehicle; and the neurosteroid, 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP; 100 or 200 ng/side), or beta-cyclodextrin vehicle. Lordosis was assessed before the series of infusions, immediately after drug infusions and 10 or 60 min after 3alpha,5alpha-THP infusions. Progestin- or progestin plus SKF38393-or muscimol-mediated increases in lordosis were blocked by DDA pretreatment. Thus, in the VTA, progestins' membrane action may involve adenylyl cyclase.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / pharmacology
  • Adenylyl Cyclases / metabolism*
  • Animals
  • Cricetinae
  • Dopamine Agonists / pharmacology
  • Estradiol / pharmacology
  • Female
  • GABA Agonists / pharmacology
  • Male
  • Motor Activity / drug effects
  • Muscimol / pharmacology
  • Posture
  • Progestins / pharmacology*
  • Rats
  • Rats, Long-Evans
  • Receptors, Dopamine D1 / drug effects
  • Receptors, GABA / drug effects
  • Sexual Behavior, Animal / drug effects*
  • Stimulation, Chemical
  • Ventral Tegmental Area / enzymology*

Substances

  • Dopamine Agonists
  • GABA Agonists
  • Progestins
  • Receptors, Dopamine D1
  • Receptors, GABA
  • Muscimol
  • Estradiol
  • 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine
  • Adenylyl Cyclases