Final answer:
H2 blockers reduce hydrochloric acid secretion by acting on parietal cells, not chief cells. If a mutation prevented GTP hydrolysis in a G-protein's alpha subunit, it would result in a more severe allergic response.
Step-by-step explanation:
The question asks about the incorrect statement regarding the use of histamine-receptor blockers, known as H2 blockers. H2 blockers actually cause the parietal cells to decrease the secretion of hydrochloric acid (HCl), not the chief cells. Moreover, these medications block H2 receptors on parietal cells in the stomach lining. Therefore, an incorrect statement might say that H2 blockers affect chief cells which is not true as they affect the parietal cells.
Regarding the reference information given, if a mutation in the G-protein's alpha subunit prevents the hydrolysis of GTP, the resulting effect would be a more severe allergic response, as the G-protein would remain active longer, continuously signaling for the effects of histamine such as itchiness and airway constriction.