Make sure response is ONE paragraph or less. We learned that neurotransmitters:

Question

Make sure response is ONE paragraph or less.

We learned that neurotransmitters:
- Are released from presynaptic terminals (in response to action potentials) into a synapse
- Bind to receptors on postsynaptic cells to produce their actions
- Are removed from the synaptic cleft to terminate their actions

The mechanisms of action of various medications and drugs are based on the presence of or clearance of various neurotransmitters within the synaptic cleft. Based on the processes of neurotransmitter release, re-uptake, and binding, describe 1) a mechanism that might contribute to potentiating a neurotransmitter’s synaptic effects and 2) a mechanism that might contribute to limiting a neurotransmitter’s synaptic effects. Provide example situations where each of these mechanisms might play a physiological role.

Explanation / Answer

The number of ion channels on the post-synaptic membrane affects the strength of the synapse. Research suggests that the density of receptors on post-synaptic membranes changes, affecting the neuron’s excitability in response to stimuli. In a dynamic process that is maintained in equilibrium, N-methyl D-aspartate receptor (NMDA receptor) and AMPA receptors are added to the membrane by exocytosis and removed by endocytosis. These processes, and by extension the number of receptors on the membrane, can be altered by synaptic activity.Experiments have shown that AMPA receptors are delivered to the synapse through vesicular membrane fusion with the postsynaptic membrane via the protein kinase CaMKII, which is activated by the influx of calcium through NMDA receptors. CaMKII also improves AMPA ionic conductance through phosphorylation ]When there is high-frequency NMDA receptor activation, there is an increase in the expression of a protein PSD-95 that increases synaptic capacity for AMPA receptors. This is what leads to a long-term increase in AMPA receptors and thus synaptic strength and plasticity.

Neurons form networks through which nerve impulses travel, each neuron often making numerous connections with other cells. These electrical signals may be excitatory or inhibitory, and, if the total of excitatory influences exceeds that of the inhibitory influences, the neuron will generate a new action potential at its axon hillock, thus transmitting the information to yet another cell.

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