Final answer:
At a glutamatergic synapse with AMPA and NMDA receptors, 1 pulse/sec tetanic stimulation is more likely to induce Long-Term Depression (LTD) due to the relatively low frequency of synaptic activity, leading to the removal of AMPA receptors from the postsynaptic membranes.
Step-by-step explanation:
The question relates to whether 1 pulse/sec tetanic stimulation of presynaptic neurons is likely to lead to Long-Term Potentiation (LTP) or Long-Term Depression (LTD) at a glutamatergic synapse containing both AMPA and NMDA receptors. Considering the mechanisms of synaptic plasticity, 1 pulse/sec is a relatively low-frequency stimulation, which is more likely to induce LTD rather than LTP.
LTP is associated with strong, repeated stimulation of a synapse that leads to the insertion of more AMPA receptors into the postsynaptic membrane, enhancing synaptic strength. Conversely, LTD involves less frequent synaptic activity, which results in the removal of AMPA receptors, thereby weakening the synaptic connection.
As such, 1 pulse/sec stimulation would not sufficiently depolarize the postsynaptic neuron to remove the magnesium block from NMDA receptors, resulting in only a small amount of Ca²⁺ entry and the initiation of signaling cascades that lead to AMPA receptor removal, hence LTD.