Following is not seen in bezold-jaisch reflex:
**Core Concept**
The Bezold-Jarisch reflex is a physiological phenomenon where activation of certain receptors in the heart and blood vessels leads to a decrease in heart rate and blood pressure. This reflex is mediated by the release of neurotransmitters and the activation of specific neural pathways.
**Why the Correct Answer is Right**
The Bezold-Jarisch reflex is characterized by a decrease in heart rate and blood pressure, which is primarily mediated by the activation of the vagus nerve and the release of acetylcholine. This reflex is often observed in response to the activation of mechanoreceptors in the heart and blood vessels, particularly the ventricular mechanoreceptors. The activation of these receptors leads to a reduction in sympathetic tone and an increase in parasympathetic tone, resulting in a decrease in heart rate and blood pressure.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the Bezold-Jarisch reflex is indeed characterized by a decrease in heart rate and blood pressure, not an increase.
**Option B:** This option is incorrect because while the Bezold-Jarisch reflex does involve the activation of the vagus nerve, it is not the only nerve involved in this reflex.
**Option C:** This option is incorrect because the Bezold-Jarisch reflex is not primarily mediated by the release of epinephrine, but rather by the release of acetylcholine.
**Clinical Pearl / High-Yield Fact**
The Bezold-Jarisch reflex is an important physiological mechanism that can be triggered by various factors, including the administration of certain medications, such as beta-blockers and calcium channel blockers. Understanding this reflex is crucial for clinicians to manage patients with cardiovascular disease effectively.
**Correct Answer: A**.