Question

What kind of chemical is released at a synapse?

Answer 1

Chemicals secreted at synapse is called as neurotransmitter

Explanation:

In synapse there are various synaptic vesicles. These vesicles have different chemicals called neurotransmitters. Chemically they are single amino acids, small polypeptides, Nitrous oxide, carbon monoxide and purines.
The neurotransmitters may be excitation or inhibition. As per the requirement the adjacent neurone may be excited or inhibited.
If the impulse is injurious then the adjacent neurone is excited for quick action. Example is pricking the finger is injurious. The limb is withdrawn.
Pleasure sensation is continued. No further neurones are stimulated but are inhibited.