Essential Biochemistry - Neurotransmitters (Section 2 - No. 31)

Which of the following statements about neurotransmitters is/are correct?

They are synthesized at the nerve ending.

They are packaged into vesicles.

They can cause excitation or inhibition.

They are released from the presynaptic neuron by exocytosis.

All statements are correct about neurotransmitters.