Environmental enrichment prevents anxiety-like behavior induced by progesterone withdrawal in two strains of rats.
Stress vulnerability could influence the treatment response to anxiety associated with abrupt hormonal suppression. The present study explored the effects of different treatments on experimental anxiety induced by progesterone withdrawal (PW) in a stress-sensitive rat strain, Wistar Kyoto (WKY), in the burying behavior test (BBT). The following experimental series was conducted using independent groups of Wistar (control strain) and WKY ovariectomized rats: Experiment 1: Rats were treated for 5days with oil, a constant dose of progesterone (0.5mg/rat, s.c) or a combination of progesterone (0.5mg/rat, s.c) plus fluoxetine (10 mg/kg, i.p); on day 6, all rats were subjected to BBT. Experiment 2: Rats received corn oil or decreasing doses of progesterone (0.84, 0.67, 0.5, 0.33 and 0.17mg/rat; one dose daily); on day 6, the rats were subjected to BBT. Experiment 3: Rats were divided into two groups that were subjected to 30days of standard conditions or environmental enrichment (EE); from days 25 to 30, all rats received a fixed dose of progesterone (0.5mg/rat, s.c.) or vehicle. On day 31, the rats were tested with BBT. Results showed that PW increased anxiety in both strains, and fluoxetine prevented anxiety in WKY rats. In contrast, a gradual reduction of progesterone prevents the anxiety in Wistar but not in WKY. EE was preventive against the anxiety induced by PW in both strains of rats. Thus, the results suggest that anxiety induced by PW is prevented by EE while the anxiolytic effect of pharmacological treatments depends on stress vulnerability.
Laboratorio de Neuropsicofarmacología, Dirección de Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente, Calzada México-Xochimilco 101, San Lorenzo Huipulco, C.P. 14370 México, D.F., Mexico.
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Islas-Preciado
Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados-IPN, Calzada de los Tenorios 235, Granjas Coapa, C.P. 14330 México, D.F., Mexico.
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López-Rubalcava
Subdirección de Investigaciones Clínicas, Instituto Nacional de Psiquiatría "Ramón de la Fuente", Calzada México-Xochimilco 101, San Lorenzo Huipulco, C.P. 14370 México, D.F., Mexico.
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González-Olvera
Laboratorio de Neuropsicofarmacología, Dirección de Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente, Calzada México-Xochimilco 101, San Lorenzo Huipulco, C.P. 14370 México, D.F., Mexico.
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Gallardo-Tenorio
Laboratorio de Neuropsicofarmacología, Dirección de Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente, Calzada México-Xochimilco 101, San Lorenzo Huipulco, C.P. 14370 México, D.F., Mexico. Electronic address: estrada@imp.edu.mx.
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Estrada-Camarena
D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D001007:Anxiety / Q000188:drug therapy*; D001522:Behavior, Animal / Q000187:drug effects*; D004777:Environment; D005260:Female; D005473:Fluoxetine / Q000494:pharmacology*; D011374:Progesterone / Q000494:pharmacology*; D011921:Rats, Inbred WKY
D014151:Anti-Anxiety Agents; D005473:Fluoxetine; D011374:Progesterone
Wistar Kyoto; burying behavior test; environmental enrichment; fluoxetine; gradual reduction of progesterone; progesterone withdrawal