For a neurotransmitter to produce an inhibitory postsynaptic potential, which of the following must occur in the postsynaptic neuron?

For a neurotransmitter to produce an inhibitory postsynaptic potential (IPSP), the following must occur in the postsynaptic neuron:

1. The neurotransmitter must bind to a specific receptor on the postsynaptic neuron. This receptor is typically a type of protein embedded in the neuron's cell membrane.

2. The binding of the neurotransmitter to the receptor triggers a change in the neuron's membrane potential. This change is typically a hyperpolarization, which means that the inside of the neuron becomes more negative compared to the outside.

3. This hyperpolarization makes it more difficult for the neuron to reach the threshold needed to fire an action potential. In other words, the neuron becomes less likely to send a signal to other neurons.

4. This decrease in the likelihood of the neuron firing an action potential is what we refer to as an inhibitory postsynaptic potential. It's a way for the nervous system to decrease the activity of certain neurons, allowing for more precise control over the body's responses to various stimuli.

So, in summary, for a neurotransmitter to produce an IPSP, it must bind to a receptor on the postsynaptic neuron, trigger a hyperpolarization of the neuron, and thereby decrease the likelihood of the neuron firing an action potential.