Question

When curare, a neuromuscular poison, is dropped onto an isolated muscle-nerve preparation in a laboratory, the muscle does not contract when the nerve is stimulated, even though neurotransmitter is released from the nerve cell. Why does this happen

Answer 1

Answer:

Explanation:

Whenever the nerve terminal's action potential depolarizes, calcium enters the cell through the channels. Calcium allows acetylcholine (ACh) to be released more easily.  These ACh molecules subsequently circulate into the synaptic cleft and attach to the motor end-plate of the nicotinic cholinergic receptors. Acetylcholine molecules connect to nicotine ion-channel receptors present on cell membrane the of muscle cells, enabling the ion channels to open. Calcium ions then enter the muscle cell, kicking off a series of events that eventually result in muscular contraction.

Curare is a kind of neuromuscular relaxant blocker that is non-depolarized in nature. Nondepolarizing muscle relaxants work as competitive agonists, binding to ACh receptors but failing to activate ion channels. As a result, they inhibit ACh from bonding, preventing the development of endplate potentials and inducing muscle paralysis.