What effect is NOT caused by histamine release?

Histamine is a compound involved in local immune responses, regulation of physiological functions in the gut, and acts as a neurotransmitter. It plays a significant role in allergic reactions and the body's response to injury. When histamine is released, it primarily causes vasodilation, increased vascular permeability, and bronchoconstriction.

The correct answer highlights that increased cardiac contractility leading to hypertension is not a direct effect of histamine release. Histamine typically has the opposite effects on blood pressure. Instead of causing increased contractility and hypertension, histamine predominantly induces vasodilation, which can lead to a drop in blood pressure (hypotension). This means that the circulatory effects of histamine are more about relaxing blood vessels rather than contracting the heart muscles or increasing blood pressure.

The other options correctly describe effects related to histamine. Vasodilation may lead to flushed skin and lowered blood pressure, smooth muscle contraction in the respiratory system can result in difficulty breathing as seen in asthma attacks, and increased vascular permeability can lead to edema as fluids leak into surrounding tissues. Thus, option B stands out because it does not align with the established physiological effects of histamine.