ABSTRACT
Orofacial neuropathic chronic pain (NCP) is frequently attributed to lesions caused by orofacial surgeries and dental treatments. there are many experimental models available to study orofacial NCP, however, many are extremely painful for the animal due to the amplitude of the innervated region. a previously proposed mental nerve constriction model, mNC, was used in this project. forty wistar rats were randomly divided into two groups: one group included rats with mNC (n=20), and another rats with sham lesions (n=20). through the use of the fixed ratio program and the progressive program, a decrease of motivation for a sweet substance, caused by the lesion, was evaluated. the possibility of alterations in cognitive learning and adaptation abilities was also assessed using the go/no-go behavioral task. the mNC group showed low induced and spontaneously evoked pain responses, as well as a decrease in the motivation for sucrose, a sign of anhedonia. this decrease does not depend on taste processing. finally, although no alterations in the learning-memory process were observed, the mNC group did show alterations when adapting to a new rule.
Subject(s)
Animals , Rats , Behavior, Animal/physiology , Facial Pain/etiology , Trigeminal Nerve Injuries/complications , Chronic Pain/etiology , Sucrose , Rats, Wistar , Disease Models, Animal , Exploratory Behavior/physiology , NeuralgiaABSTRACT
Resumen: El objetivo principal de la presente investigación fue evaluar los efectos del agonista 5-HT2C Ro 60-0175 en la expresión de la sensibilización locomotora inducida por la administración de etanol. Además, también se evaluaron los efectos del antagonista 5-HT2C SB 242084 sobre los efectos del Ro 60-0175 en la sensibilización locomotora producida por etanol para determinar si los efectos del Ro 60-0175 resultan de una acción específica sobre los receptores 5-HT2C. Diferentes grupos de ratas se sometieron al desarrollo de sensibilización locomotora producida por etanol. En las pruebas de expresión de la sensibilización locomotora se evaluaron los efectos del Ro 60-0175 y del SB 242084 sobre la sensibilización locomotora producida por etanol. Adicionalmente se evaluó el pretratamiento con SB 242084 sobre los efectos del Ro 60-0175 en la sensibilización locomotora producida por etanol. Los resultados mostraron que el Ro 60-0175 disminuyó la sensibilización locomotora producida por etanol y que este efecto fue prevenido por el pretratamiento con SB 242084. Estos resultados sugieren que los receptores 5-HT2C juegan un papel modulatorio en la sensibilización locomotora producida por etanol.
Abstract: The main goal of the present research was to evaluate the effects of 5-HT2C receptor agonist Ro 60-0175 on the expression of ethanol-induced locomotor sensitization. In order to determine if these effects result from a specific action of Ro 60-0175 on 5-HT2C receptors, we also examined the effects of the selective 5-HT2C receptor antagonist SB 242084 on Ro 60-0175's effects on the ethanol-induced locomotor sensitization. Different groups of rats were subjected to development of ethanol-induced locomotor sensitization. On the expression tests of the locomotor sensitization the effects of the Ro 60-0175 and SB 242084 on the ethanol-induced locomotor sensitization were evaluated. In addition, the pretreatment with SB 242084 on the effects of Ro 60-0175 on the ethanol-induced locomotor sensitization was also evaluated. The results showed that Ro 60-0175 produced a dose-dependent prevention of the expression of ethanol-induced locomotor sensitization. This effect was reversed by administration of SB 242084. These data suggest that 5-HT2C receptors play a regulatory role on ethanol-induced locomotor sensitization.
ABSTRACT
Resumen En esta investigación se evaluaron los efectos de la administración sistémica del antagonista GABAA bicuculina sobre los efectos del agonista 5-HT1A 8-OH-DPAT en las propiedades discriminativas de la anfetamina (ANF) utilizando el condicionamiento de aversión a los sabores. Los resultados mostraron que ni el 8-OH-DPAT, ni la bicuculina, sustituyeron la señal discriminativa de la ANF. Sin embargo, la administración del 8-OH-DPAT disminuyó la señal discriminativa de la ANF, y la administración de la bicuculina, previa a la administración del 8-OH-DPAT más una dosis de ANF, previno el efecto del 8-OH-DPAT sobre la señal discriminativa de la ANF. Estos datos apoyan la hipótesis de que las conductas relacionadas con la adicción a las drogas, como la ANF, involucran diferentes sistemas de neurotransmisión como la DA, la 5-HT y el GABA.
Abstract In this research, the effects of systemic administration of the GABAA receptor antagonist bicuculline on the effects of 5-HT1A receptor agonist 8-OH-DPAT on the discriminative properties of the AMPH using the conditioned taste aversion procedure were evaluated. The results showed that neither 8-OH-DPAT nor bicuculline administration did not substitute for AMPH. However, the 8-OH-DPAT administration decreased the discriminative signal of AMPH and the bicuculline administration, prior to the 8-OH-DPAT administration plus a dose of AMPH prevented the effect of the 8-OH-DPAT on discriminative signal of AMPH. These data support the hypothesis that addiction-related behaviors of drugs such as AMPH involve several neurotransmitter systems such as DA, 5-HT and GABA.