Question

what is the effect of the binding of neurotransmitters to their receptors on the postsynaptic cell membrane?
multiple choice
neurotransmitters are sometimes excitatory and sometimes inhibitory.
neurotransmitters are always inhibitory.
neurotransmitters are always excitatory.

Explanation:

Neurotransmitters can have different effects. Some, like glutamate, are excitatory (increase the likelihood of the post - synaptic neuron firing). Others, like GABA, are inhibitory (decrease the likelihood of the post - synaptic neuron firing). So they are not always one or the other.

Answer:

Neurotransmitters are sometimes excitatory and sometimes inhibitory.