Psicothema was founded in Asturias (northern Spain) in 1989, and is published jointly by the Psychology Faculty of the University of Oviedo and the Psychological Association of the Principality of Asturias (Colegio Oficial de Psicología del Principado de Asturias).
We currently publish four issues per year, which accounts for some 100 articles annually. We admit work from both the basic and applied research fields, and from all areas of Psychology, all manuscripts being anonymously reviewed prior to publication.

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Effects of phosphodieastrase type 5 inhibitions on morphine withdrawal symptoms in mice

Minoo Mahmoodi1, Siamak Shahidi2 and Nasrin Hashemi-Firouzi2

1 Islamic Azad University, Hamadan Branch (Irán) and
2 Hamadan University of Medical Sciences (Irán)

Background:Chronic morphine exposure creates dependence and, upon cessation, withdrawal symptoms. Studies indicate the phosphodiesterase type 5 (PDE5) inhibitor sildenafil may provide centrally mediated benefits against withdrawal, and therefore, this study evaluated morphine withdrawal signs in dependent mice with and without sildenafil treatment. Method: Dependence was induced by repeated treatments with morphine over 5 consecutive days. The morphine-dependent mice received sildenafil (1, 5, 10, or 20 mg/kg, i.p.) 15 min prior to the precipitation of morphine withdrawal. On the last day, naloxone was injected 2 hours after the last morphine injection, and withdrawal signs were evaluated for 30 min after naloxone injection. Results: The administration of sildenafil reduced all of the morphine withdrawal symptoms. Conclusions: The administration of sildenafil diminished morphine withdrawal signs in morphine-dependent mice. We hypothesize that the mechanism involves enhanced cyclic guanosine monophosphate (cGMP) activity, but further studies are recommended for a better understanding.

Efectos comportamentales por inhibición de la fosfodiesterasa tipo 5 sobre los síntomas de abstinencia de morfina en ratones. Antecedentes: se sabe que la exposición crónica a la morfina conduce a la dependencia. El cese en el consumo de morfina conlleva al desarrollo del síndrome de abstinencia. Numerosos estudios indican los efectos beneficiosos del sildenafil en el sistema nervioso central. Es por ello que el presente estudio evaluó el efecto del sildenafil sobre el síndrome de abstinencia a la morfina. Método: los ratones dependientes de morfina recibieron dosis diferentes de sildenafil (1, 5, 10 o 20 mg/kg i.p.) 15 minutos antes de producir el síndrome de abstinencia a la morfina. En el último día, la naloxona se inyectó dos horas después de la última inyección de morfina. Los signos de abstinencia fueron evaluados durante 30 minutos después de la inyección de naloxona. Resultados: la administración de sildenafil redujo todos los síntomas de abstinencia relacionados con la morfina. Conclusiones: se puede concluir que la administración de sildenafil disminuyó los signos de abstinencia a la morfina. Estos resultados muestran cómo los incrementos en el nivel del GMP cíclico mediante la vía PDE5 reduce los síntomas de abstinencia a la morfina.


Impact factor 2022:  JCR WOS 2022:  FI = 3.6 (Q2);  JCI = 1.21 (Q1) / SCOPUS 2023:  SJR = 1.07;  CiteScore = 6.4 (Q1)