The endogenous opioid system modulates defensive behavior evoked by Crotalus durissus terrificus: panicolytic-like effect of intracollicular non-selective opioid receptors blockade - Calvo, Fabrício; Lobão-Soares, Bruno; Freitas, Renato Leonardo de; Maurin, Tatiana Paschoalin; Anjos-Garcia, Tayllon dos; Medeiros, Priscila; Silva, Juliana Almeida da; Lovick, Thelma Anderson; Coimbra, Norberto Cysne (Journal of Psychopharmacology, 2019)