HRH3 and obesity due to melanocortin 4 receptor deficiency: The H3 histamine receptor antagonists (i.e. NNC 38-1049, NNC 38-1202, JNJ-5207852, GT-2394, A-423579; A-631972, A-331440) supress food intake and cause profound weight loss in various obesity rodent models (Barbier et al. 2004; Yates et al. 2002; Hancock and Brune 2005; Malmlöf et al. 2005, 2006).