Final answer:
Ca²⁺-calmodulin kinase mediates synaptic strengthening during LTP by phosphorylating AMPA receptors, enhancing their conduction and increasing their number in the postsynaptic membrane.
Step-by-step explanation:
The special property of Ca²⁺-calmodulin kinase that allows it to mediate the early stages of synaptic strengthening during LTP is its ability to phosphorylate various postsynaptic targets, including AMPA receptors.
During LTP, Ca²⁺ ions entering the cell initiate a signaling cascade that activates Ca²⁺-calmodulin kinase. This kinase then phosphorylates AMPA receptors, enhancing single channel conduction and increasing the number of AMPA receptors in the postsynaptic membrane.
By phosphorylating AMPA receptors, Ca²⁺-calmodulin kinase strengthens the synaptic connection, making the postsynaptic neuron more likely to fire in response to presynaptic neurotransmitter release.