Study on the distribution sites and the molecular mechanism of analgesia after intracerebroventricular injection of rat/mouse hemokinin-1 in mice

► We firstly demonstrated the distribution sites of r/m HK-1 in mouse brain. ► The analgesia of r/m HK-1 is induced by the activation of NK1 receptor firstly. ► The analgesia of r/m HK-1 is also related to the expression increase of MOR and POMC.