Morphine attenuated the anxiety-like behaviour associated to acetic acid-induced visceral pain in adolescent male, but not in female mice lacking CB1 receptors.

GRACIELA BALERIO; ANDRÉS VARANI; VALERIA PEDRÓN; ELIANA CANERO; VIRGINIA PEREZ

Glasgow

Congreso; FENS 2020 Virtual Forum of Neuroscience; 2020

Previous studies revealed a differential sex dependent effect on anxiety-like behavior in CB1 cannabinoid receptor deficient mice (CB1KO) on the elevated plus maze (1). The elevated plus maze is a valid test of anxiety-like behavior in rodents and has been used to screen pharmacotherapies for affective disorders (2). On the other hand, high doses of morphine (MOR) showed anxiogenic-like effect while low doses of MOR induced anxiolytic-like effect administered in rats and mice (3, 4).Depression and anxiety are associated with increased perception of pain severity, whereas prolonged duration of acute pain leads to increased mood dysregulation. (5).Intraperitoneal injection of diluted solutions of acetic acid is a well-established animal model to study visceral pain in rodents (writhing test) (6). The aim of the present study was to evaluate the interaction between the CB1 cannabinoid receptors and the endogenous opioid system by assaying anxiety like-behaviour related to acetic acid-induced visceral pain in adolescent mice of both sexes lacking CB1 receptors.References: 1-Bowers ME, Ressler KJ., Behav Brain Res. (2016); 1,300: 65-9. 2-Walf AA, Frye CA., Nature protocols. (2007); 2:322?8.3-Motta V, Brandão ML. Pharmacol. Biochem. Behav. 1993;44(1):119-25.4-Shin IC, et al., Pharmacology (2003); 68:183?189.5-Michaelides & Zis. Postgraduate Medicine. (2019); 131: 438-4446- Nakamura H. & Shimizu M., Br. J. Pharmac., . (1981); 73, 779-785