κ-opioid receptor as a key mediator in the regulation of appetitive 50-kHz ultrasonic vocalizations. - Hamed, Adam; Szyndler, Janusz; Taracha, Ewa; Turzyńska, Danuta; Sobolewska, Alicja; Lehner, Małgorzata; Krząścik, Paweł; Daszczuk, Patrycja (Psychopharmacology, 2015)