Histamine and Antihistamines NARRATED animation.1970-01-01T00:00:00+00:00Functions of histamine, the 4 H-receptors, H1-antihistamines first and second generations.PT207Shttps://d38zjy0x98992m.cloudfront.net/3dae375e-c1b1-4158-94fa-2ddccd507d3d/antihistamines_narrated_xlarge.jpghttps://d38zjy0x98992m.cloudfront.net/3dae375e-c1b1-4158-94fa-2ddccd507d3d/antihistamines_narrated_mp4_hd_video.mp4