Capsaicin produces antidepressant-like effects in the forced swimming test and enhances the response of a sub-effective dose of amitriptyline in rats

Publication date: Available online 20 August 2018Source: Physiology & BehaviorAuthor(s): Miriam Reyes-Mendez, Luis Castro-Sánchez, Adan Dagnino-Acosta, Irving Aguilar-Martinez, Azucena Pérez-Burgos, Clemente Vázquez-Jiménez, Eloy G. Moreno-Galindo, Fernando J. Álvarez-Cervera, José L. Góngora-Alfaro, Ricardo A. Navarro-Polanco, Javier AlamillaAbstractTransient receptor potential vanilloid 1 (TRPV1) channels have been implicated in depression and anxiety. The aim of this study was to evaluate the antidepressant-like properties of the TRPV1 agonist capsaicin using the forced swimming test (FST) in rats. Capsaicin (0.001–0.25 mg/kg, i.p.) produced a reduction of immobility in the FST. A maximally effective dose of the tricyclic antidepressant amitriptyline (12 mg/kg) reduced immobility as well. Notably, doses of capsaicin (1 pg/kg, 1 ng/kg, and 0.001 mg/kg) that were ineffective when applied alone produced a significant decrease in immobility when combined with a subthreshold dose of amitriptyline (5 mg/kg). Rats treated with capsaicin (0.01 mg/kg) + amitriptyline (5 mg/kg) displayed less immobility than those treated with a maximally effective dose of amitriptyline. The non-pungent TRPV1 channel agonist palvanil (0.05–0.1 mg/kg, i.p.) also decreased immobility in the FST. Capsaicin (0.05 mg/kg) did not affect general locomotion in the open field test, nor performance in the elevated plus maze, or skeletal muscle contraction strength measured i...
Source: Physiology and Behavior - Category: Physiology Source Type: research