Neurotransmitter

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Neurotransmitter

• 2 group (Ajou, Sogang Univ.)

An Bum-Chu, Lee Kyung-Bun
ACADEMYIC CONFERENCE OF LIFE SCIENCE
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Content

• Introduction
• Neurotransmitter
• Definition, synthesis storage, Release,
  Recovery degradation, discovery
• Receptor
• Receptor type (transmitter-gated ion channel,
  G-protein coupled receptor)
• AChR, GABAAR, Dopamine receptor, Glutamate
  receptor, Opioid receptor
• Neuropharmacology
• Agonist and Antagonist
• Cocaine Amphetamine, Caffeine, opioid,
  nicotine, alcohol

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Introduction

• Why should we study neurotransmitter about
  addiction?
• How will we study neurotransmitter about
  addiction?

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Definition

• The molecule must be synthesized and stored in
  the presynaptic neuron.
• The molecule must be released by the presynaptic
  axon terminal upon stimulation.
• The molecule, when experimentally applied, must
  produce a response in the postsynaptic cell that
  mimics the response produced by the release of
  neurotransmitter from the presynaptic neuron.

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Classification

• Amino acid
• Amine
• Peptide

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Synthesis Storage

• Amino acid Amine
• Peptide

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Synthesis Storage

• Colinergic neuron
• Catecholaminergic neuron
• Serotoninergic neuron
• Amino acidergic neuron

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Release

• Arrival of AP
• Ca2 channel open (voltage dependent)
• Ca2 influx
• Exocytosis (synaptic vesicle)

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Recovery Degradation

• Diffusion
• Reuptake
• Presynapse transport glia transport
• Degradation
• Degradation by enzyme

AChE
acetylcolin
Acetate choline
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Discovery

• Immuno - cytochemistry
• In situ hybridization

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Receptor

• Receptor type
• AChR (Acetylcoline receptor)
• GABAA receptor
• Dopamine receptor
• Glutamate receptor
• Opioid receptor

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Receptor Type

• Transmitter-gated ion channel
• IPSP (inhibitatory postsynaptic potential)
• EPSP (excitatory postsynaptic potential)
• G-protein coupled receptor
• Shortcut pathway
• Second messenger cascade

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(acetylcolin receptor) AChR

• nAChR
• Skeletal muscle
• Transmitter-gated ion channel
• 4 subunit pentamer
• mAChR
• Cardiac muscle
• G protein-coupled receptor
• 4 subtype (m1, m2, m3, m4)

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GABAA Receptor

• Transmitter-gated ion channel
• Cl- ion influx (IPSP)

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Dopamine Receptor

• G-protein coupled receptor
• D1-like family (D1, D5)
• D2-like family (D2-D2L D2S, D3, D4)

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Glutamate Receptor

• AMPA, NMDA, kainate
• Transmitter-gated ion channel
• Mechanism

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Opioid Receptor

• Antinociception
• G-protein coupled receptor
• Subtype
• µ (µ1µ2), d(d1d2), ?(?1?2?3)

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Neuropharmacology

• Antagonist agonist
• Action of addictive drugs
• Coanine amphetamine
• Caffeine
• Opioites
• Nicotine
• Alcohol

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Action of addictive drugs

• drug imitation or inhibition of secretion of
  specific neurotransmitter
• antagonist
• Blocking of specific neurotransmitter
• agonist
• Imitation or increase of neurotransmitter
• The ways the drug can affect the synaptic
  transmission

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Action of addictive drugs

• Dopamine-neurotransmitter of CNS
• synthesis, storage, release
• actions of dopamine
• Dopaminergic nigro-neostriatal pathway
• Mesolimbic dopaminergic pathway
• Tubo-infundidular system

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• Mesolimbic dopaminergic reward system

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Cocaine Amphetamine

• Mechanism
• Cocaine and amphetamine ? binding to dopamine
  reuptake trandporter ? inhibition of dopamine
  reuptake? accumulation of dopamine in synapse ?
  stimulation of receptor ? incresed dopamine
  activity
• Actions of cocaine amphetamine temporary
• Autoreceptor
• Flash (add cocaine, without cocaine)
• Amphetame-powerfully dopamine releases -mentaliy,
  physically

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Inhibition of dopamine reuptake

• Other drug
• ex.cocaine, amphetamine, domperidone

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Caffeine

• Caffeine
• action heart rate increase, blood vessel
  constriction , headache
• Inhibition of adenosine
• adenosine inhibition of dopamine release
• As a result, increase of dopamine release

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Opiates

• Morphine, heroin
• endolphin neurotransmitter released from brain
• endolphin opiates ? receptor ? excite of
  periaqueductal gray area ? decreased secretion of
  P substance ? decreased pain

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• Pain pathway

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• pathway of analgesia suppression

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Nicotine

• Chemical in cigarette
• nicotinic receptor(acethycholine receptor)
  blocking
• Binding to receptor that increase the sectretion
  of doapmine in nucleus accumbens ? reinforce
• Catecholamine release ? rised blood pressure,
  perspiration

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nicotinic receptor and its action
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Alcohol

• Disfunction of recognition (inference, memory
  etc)
• Influx inhibition of Na ? prevention of nerve
  system
• Decrease of serotonin, activation of GABA receptor