Which of the following statement about ‘Cadaveric spasm’ is not true?
**Core Concept:** Cadaveric spasm is a condition characterized by involuntary contraction of smooth muscles, often seen in cadavers but can also occur in living individuals. It is due to the release of stored acetylcholine from the presynaptic neurons and its interaction with acetylcholine receptors on the postsynaptic smooth muscle cells.
**Why the Correct Answer is Right:** Cadaveric spasm occurs as a result of the release of stored acetylcholine from the presynaptic neurons in the autonomic nervous system. This acetylcholine then binds to the nicotinic acetylcholine receptors on the postsynaptic smooth muscle cells, leading to their involuntary contraction. The correct answer, **D**, states that "Cadaveric spasm is caused by direct stimulation of the acetylcholine receptors", which is incorrect.
Cadaveric spasm is not caused by direct stimulation of the acetylcholine receptors. Instead, it is due to the release of stored acetylcholine from the presynaptic neurons, which binds to the nicotinic acetylcholine receptors on the postsynaptic smooth muscle cells, leading to their involuntary contraction.
**Why Each Wrong Option is Incorrect:**
A. This statement is incorrect because cadaveric spasm results from the release of stored acetylcholine, not its direct stimulation.
B. This statement is incorrect because cadaveric spasm occurs due to the release of stored acetylcholine, not its direct stimulation.
C. This statement is incorrect because cadaveric spasm is not caused by the direct stimulation of acetylcholine receptors, but rather due to the release of stored acetylcholine.
**Clinical Pearl:** Understanding the underlying mechanisms of cadaveric spasm is crucial for accurate diagnosis and treatment of related conditions. For instance, in living patients, it may be mistaken for a genuine medical emergency, leading to unnecessary interventions.
**Explanation of Wrong Options:**
Option A and B both incorrectly attribute the cause of cadaveric spasm to direct stimulation of acetylcholine receptors. In reality, it is the release of stored acetylcholine due to neuronal damage or disruption that leads to cadaveric spasm.
Option C is also incorrect because it falsely claims that the stimulation of acetylcholine receptors causes cadaveric spasm. Instead, the condition is due to the release of stored acetylcholine following neuronal damage or disruption.