1. Neurotransmitters and its
mechanism of action
Presented by
R.Parthasarathy

2. INTRODUCTION:
What is neurotransmitter
Criteria
General characteristics features
Classification biochemical
physiological
Mechanism of action of individual chemical

3. ANATOMY OF NERVE:
Postsynaptic:
Muscle  Contraction
Neuron  Action potential
Glands  Secretion

4. DEFINITION:
Neurotransmitters are the
chemical substances
which are responsible for
transmission
of an impulse through a
synapse.
Schematic diagram of synapse

5. CRETIA: 50 substance are there
 Synthesized by pre-synaptic neurons with the help
of synthesizing enzyme and stored in vesicles at
axon terminal.
 Stimulation of nerve cause release of transmitters.
 Travels between pre to post-synpatic membrane.
 Associated with an enzyme system(inactivation).
 Mimic the effects of nerve stimulation outside.
 Drugs which modifies nerve stimulation also
modifies transmitter action the similar way.

6. Neuromediators or neurohormones:
Neuromodulators:
Neuromodulators:
Eg: VIP,somatostatin,ckk,substance P etc

7. ACTION OF NEUROTRANSMITTERS
general characteristics
Neurotransmitter travels pre  post synaptic
Receptors associated with Ion channels and
enzyme(second messenger)
Acts in milliseconds
Activate both pre and post synaptic receptors.
More transmitter interact both pre and post
synaptically (Sp Rec & sp effects)

8. CLASSIFICATION: BIOCHEMICALLY

9. PYSIOLOGICALLY
EXCITATORY INHIBITORY
Eg:Acetylcholine GABA
Aspartate Glycine
Dopamine
Histamine
Norepinephrine
Epinephrine
Glutamate
Serotonin

10. Excitatory neurotransmitters:

11. Inhibitory neurotransmitters:

12. Acetycholine:
SYNTHESIS:
• Vasodilation,
• cardiac inhibition,
• GI peristalsis;
• control of thought, mood, sleep, muscles, bladder,
sweat glands

13. SYNTESIS
Catecholamines:
Dopamine:
Control of movements(parkinsonism)
Induction of vomiting
Inhibition of prolactin secretion
Stimulation of GnRH
Schizophrenia

14. Serotonin:
SYNTHESIS:
FUNCTIONS:
Regulation
Carbohydrate intake &
Hypthalamic releasing hormone
Pain inhibition
Hallucinations and 5HT
Depression of mood

15. Histamine:
SYNTHESIS:

16. Amino acid:
SYNTHESIS:

17. OVERVIEW
.

18. Neuropeptide transmitters:

19. General mechanism of action

29. Acetylcholine esterase

32. Thank you