title: Chronic administration of tibolone modulates anxiety-like behavior and enhances cognitive performance in ovariectomized rats.
abstract: Hormone replacement therapy (HRT) may be prescribed to prevent the symptoms of menopause. This therapy may include estrogenic and/or progestin components and may increase the incidence of endometrial and breast cancers. Tibolone (TIB), which is also made up of estrogen and progestin components, is often used to reduce the impact of HRT. However, the effect of TIB on the processes of learning, memory and anxiety has yet to be fully elucidated. The aim of this study was to evaluate the long-term effect on learning, memory processes and anxiety in ovariectomized rats caused by different doses of TIB (0 mg/kg, 0.01 mg/kg, 0.1 mg/kg 1.0 mg/kg and 10 mg/kg, administered daily via the oral route for 18 weeks). Two behavioral animal models, the autoshaping and T maze models were employed. The concentrations of acetyl choline transferase (ChAT) and tryptophan hydroxylase (TPH) in the hippocampus were directly measured by Western blot. No significant changes were observed in the autoshaping model and spontaneous activity test. In the T maze, increased latency was observed with TIB doses of 1 and 10 mg/kg compared to the vehicle. We observed that the ChAT content decreased with increasing doses of TIB, whereas TPH content increased with doses of 1 and 10 mg/kg of TIB. These data indicate that high doses of TIB improved emotional learning, which may be related to the modulation of the cholinergic and serotonergic systems by TIB.
authors: Escuela Superior de Medicina del Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón S/N, Col. Sto. Tomás, México D.F. 11340, Mexico.
authors: Judith
authors: J
authors: Espinosa-Raya
authors: Teresa
authors: T
authors: Neri-Gómez
authors: Sandra
authors: S
authors: Orozco-Suárez
authors: María G
authors: MG
authors: Campos
authors: Christian
authors: C
authors: Guerra-Araiza
mesh_terms: D000818:Animals; D001007:Anxiety / Q000188:drug therapy*; D001522:Behavior, Animal / Q000187:drug effects; D002795:Choline O-Acetyltransferase / Q000032:analysis; D003071:Cognition / Q000187:drug effects*; D020847:Estrogen Receptor Modulators / Q000008:administration & dosage* / Q000009:adverse effects; D015914:Estrogen Replacement Therapy / Q000009:adverse effects / Q000379:methods*; D005260:Female; D006624:Hippocampus / Q000201:enzymology; D018782:Maze Learning / Q000187:drug effects; D009652:Norpregnenes / Q000008:administration & dosage* / Q000009:adverse effects; D010052:Ovariectomy; D051381:Rats; D014365:Tryptophan Hydroxylase / Q000032:analysis
chemical_list: D020847:Estrogen Receptor Modulators; D009652:Norpregnenes; D014365:Tryptophan Hydroxylase; D002795:Choline O-Acetyltransferase; C027385:tibolone