Neurotransmitters
We know that transmission of signals from nerves to muscles is affected by acetylcholine a transmitter substance. Similarly neuron-neuron transmission is also achieved by acetylcholine. But there are several other chemicals that function as neurotransmitters. A limited number has already been identified and new ones are being identified rapidly.
A chemical can be called a neurotransmitter in a given tissue only if it fulfils certain conditions like:
- When applied to the postsynaptic membrane it should be able to produce the same effect as does presynaptic stimulation
- It should also be released by the presynaptic membrane
- Its action should be blocked by the same agents that block neural transmission.