Final answer:
SNAREs are protein complexes involved in neurotransmitter release, aiding membrane fusion in cells. N-ethylmaleimide, which is sometimes confused with SNARE due to its acronym, is in fact a chemical inhibitor of enzymes. Neurotransmitters, like acetylcholine released at the neuromuscular junction, act via binding to specific receptors on target cells.
Step-by-step explanation:
When considering the substance N-ethylmaleimide (SNARE), it is essential to recognize that it refers to a particular aspect of cellular function and not the SNARE (Soluble NSF Attachment Protein Receptor) complex itself. SNAREs are indeed protein complexes involved in membrane fusion, specifically in the process of neurotransmitter release. They are crucial in the docking and release of neurotransmitter-containing vesicles at the presynaptic membrane. However, N-ethylmaleimide is not a type of SNARE; rather, it is a chemical inhibitor of enzyme activity, often used in experiments to understand protein function and interactions by irreversibly binding to and modifying sulfhydryl groups on cysteine residues within proteins.
Neurotransmitters are chemical signals released from the synaptic end bulb of a neuron to elicit changes in target cells. These neurotransmitters are often inactivated by enzymes in the synaptic cleft to terminate signaling. At the neuromuscular junction, the specific neurotransmitter released is acetylcholine, which binds to nicotinic receptors and causes muscular contractions. Importantly, the effect a neurotransmitter has on a target cell is dictated by the receptor to which it binds, including ionotropic receptors like ligand-gated ion channels, and metabotropic receptors which result in metabolic changes within the cell.