title: Anxiolytic-like effect of quinpirole in combination with a low dose of 17β-estradiol in ovariectomized rats.
abstract: The aim of this study was to explore effects on anxiety-like behavior of the D2 dopamine receptor agonist, quinpirole and of the D2 dopamine receptor antagonist, sulpiride given alone or in combination with a low dose of 17β-estradiol (17β-E2) to ovariectomized (OVX) rats. Two weeks after surgery, OVX rats began 14 days of treatment with the vehicle, a low dose of 17β-E2 (5.0 μg/rat, s.c.), quinpirole (0.1 mg/kg, i.p.), sulpiride (10.0 mg/kg, i.p.), quinpirole plus 17β-E2 or sulpiride plus 17β-E2. The animals were then tested in the black and white model (BWM) and the open field test (OFT). Quinpirole (0.1 mg/kg, i.p.) administered alone or in a combination with a low dose of 17β-E2 (5.0 μg/rat, s.c.) resulted in anxiolytic-like effect in OVX rats in the BWM. Repeated treatment of quinpirole and 17β-E2 profoundly increased anxiolytic-like effect of the single substances they exert per se. Co-administration of quinpirole with 17β-E2 increased frequency of rearing and grooming in OVX rats in the OFT. Sulpiride (10.0 mg/kg, i.p.) treatment failed to alter anxiety-like behavior in OVX rats in the BWM. In addition, sulpiride blocked the anxiolytic-like effect of 17β-E2 in OVX rats. Application of neither sulpiride nor sulpiride plus 17β-E2 led to any changes of rearing and grooming behavior in OVX rats in the OFT. The results of the present study suggest that 17β-E2 and quinpirole interact to exert anxiolytic-like action and that each of these drugs can potentiate effects of each other. Further research is needed to elucidate detailed mechanisms by which quinpirole and 17β-E2 exert synergistic effect on anxiety-related behavior.
authors.affiliation: I. P. Pavlov Institute of Physiology of the Russian Academy of Science Laboratory of Neuroendocrinology St. Petersburg Russia I. P. Pavlov Institute of Physiology of the Russian Academy of Science Emb. Makarova 6 St. Petersburg 199034 Russia.
authors.forename: Julia
authors.initials: J
authors.lastname: Fedotova
mesh_terms: D000818:Animals; D001007:Anxiety / Q000188:drug therapy*; D001008:Anxiety Disorders / Q000188:drug therapy; D018491:Dopamine Agonists / Q000627:therapeutic use*; D018492:Dopamine Antagonists / Q000627:therapeutic use*; D065127:Dopamine D2 Receptor Antagonists; D004353:Drug Evaluation, Preclinical; D004359:Drug Therapy, Combination; D004958:Estradiol / Q000627:therapeutic use; D004967:Estrogens / Q000627:therapeutic use; D005260:Female; D010052:Ovariectomy; D019257:Quinpirole / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar; D017448:Receptors, Dopamine D2 / Q000819:agonists; D013469:Sulpiride / Q000627:therapeutic use*
chemical_list: D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D065127:Dopamine D2 Receptor Antagonists; D004967:Estrogens; D017448:Receptors, Dopamine D2; D019257:Quinpirole; D004958:Estradiol; D013469:Sulpiride