1. 2020;23;E581-E590Chronic Pregabalin Treatment Ameliorates Pain, but not Depressive-Like Behaviors, in a Reserpine-Induced Myalgia Model in Rats
   Randomized Animal Study
   Eva M. Gonzalez-Soler, PhD, Arantxa Blasco-Serra, PhD, Gloria M. Alfosea-Cuadrado, PhD student, Marta Igual-Lopez, PhD student, Jorge Orduna-Valls, MD, Carlos Tornero-Tornero, PhD, and Alfonso A. Valverde-Navarro, PhD.

BACKGROUND: Anticonvulsants are often prescribed as coanalgesics for pathologies presenting chronic pain, such as chronic neuropathic pain and fibromyalgia. These pathologies are associated with a wide range of comorbidities: chronic fatigue, cognitive impairment, sleep disturbances, and mood disorders. Pregabalin, an anticonvulsant used to treat fibromyalgia syndrome, has been proven to improve pain and fatigue symptoms. However, most studies have not considered the analytic effect of this drug on comorbid depressive-like symptoms in this syndrome.

OBJECTIVES: The main study objective was to examine the role of pregabalin in depressive symptomatology comorbid to chronic widespread pain using a reserpine-induced myalgia model.

STUDY DESIGN: A randomized, controlled, animal study.

SETTING: Research and data analyses were performed at the GESADA laboratory, Department of Human Anatomy and Embryology, University of Valencia, Spain.

METHODS: Forty-six Sprague-Dawley male rats were used. Acute chronic pregabalin administration was tested for depressive-like behaviors (Forced Swimming and Novelty-Suppressed Feeding Tests) and for alteration of pain thresholds (tactile allodynia, Electronic Von Frey test; and mechanical hyperalgesia, Randall and Selitto test). The same procedures were followed with duloxetine as a positive control.

RESULTS: Pregabalin significantly improved depressive-like behaviors in acute, but not chronic treatment, and significantly ameliorated pain thresholds.

LIMITATIONS: Lack of histological and electrophysiological tests.

CONCLUSIONS: Pregabalin is not effective in depressive-like symptoms associated with chronic pain but might play an acute antidepressive-like role given its antinociceptive effect.

KEY WORDS: Pregabalin, duloxetine, pain, chronic pain, comorbid depression, fibromyalgia, RIM, animal model