Release of a neurotransmitter across the synapse is triggered by the entry of Ca++ into the presynaptic axon. No Ca++ entry means no transmission across the synapse.
If the calcium ion channels in the axon terminal were blocked, then no synaptic transmission occurs.
Explanation:
The synapse has 2 parts one is post synaptic cleft and other is pre synaptic cleft. The pre synaptic cleft contains synaptic vesicles which have neurotransmitters. These neurotransmitters are in the inactive form.
When the calcium ion is coming and bind with the vesicle, the neurotransmitter gets activated. Then the vesicle binds with another protein and releases the neurotransmitter to the post synaptic vesicle. Thus information goes from pre synaptic cleft to post synaptic cleft and synaptic transmission occurs.
If the calcium ion channel is blocked, no calcium ions come into the axon terminal, the neurotransmitter can't active and no synaptic transmission happens.
