The answer is Gastrin. The Main secretion of pyloric cells are Mucus from mucous cells are Gastrin from gastrin cells which stimulates production of HCl. Ach, Gastrin stimulate ECL cell and this one secrete Histamine then stimulating Parietal cell. Cephalic Phase: 40% Mechanoreceptors and chemoreceptors in oral and nasal cavity. Engages neural responses.