Blockade of dynein would most directly reduce which neuronal process?

• A. Vesicle release
• B. Fast anterograde axonal transport
• C. Retrograde axonal transport
• D. Neurotransmitter reuptake

Answer: (C)

Dynein is the motor that moves cargo toward the minus ends of microtubules, which powers retrograde axonal transport from the synaptic terminal back to the cell body. If dynein is blocked, this backward transport is directly impaired, so signaling endosomes, neurotrophic receptors, and other materials can't efficiently reach the soma. In contrast, fast anterograde transport is driven by kinesin toward the terminal and would be largely unaffected by dynein inhibition. Vesicle release at the synapse depends on calcium-triggered exocytosis rather than motor-based transport along the axon, and neurotransmitter reuptake happens at the presynaptic membrane as a transporter process, not along the axon via dynein. Therefore, retrograde axonal transport is the process most directly reduced.