Neurotransmitter

#2 group (Ajou, Sogang Univ.)

ACADEMYIC CONFERENCE OF LIFE SCIENCE

An Bum-Chu, Lee Kyung-Bun

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

Introduction

Why should we study neurotransmitter about addiction?

How will we study neurotransmitter about addiction?

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.

Classification Amino

acid

Amine

Peptide

cholestokininacetylcolineGABA

dynorphinDopamineglutamate

enkephalinesepinephrineglycine

NAAGhistamine

Neuropeptide Ynorepinephrine

somatostatinserotonine

Substance PThyropin-releasing

hormoneVasoactive intestinal

polypeptide

Major neurotransmitterPEPTIDEAMINEAMINO ACID

Synthesis & Storage

Amino acid & Amine

Peptide

Synthesis & Storage

Colinergic neuron

Catecholaminergic neuron

Serotoninergic neuron

Amino acidergic neuron

Release Arrival of AP

Ca2+ channel open (voltage dependent)

Ca2+ influx

Exocytosis (synaptic vesicle)

Recovery & Degradation

Diffusion Reuptake

Presynapse transport & glia transport Degradation

Degradation by enzyme

acetylcolin

Acetate + choline

AChE

Discovery Immuno -

cytochemistry

In situ hybridization

Receptor Receptor type

AChR (Acetylcoline receptor)

GABAA receptor

Dopamine receptor

Glutamate receptor

Opioid receptor

Receptor Type Transmitter-gated

ion channel IPSP (inhibitatory

postsynaptic potential) EPSP (excitatory

postsynaptic potential)

G-protein coupled receptor Shortcut pathway Second messenger cascade

(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)

Transmitter-gated ion channel

Cl- ion influx (IPSP)

GABAA Receptor

G-protein coupled receptor

D1-like family (D1, D5)

D2-like family (D2-D2L · D2S, D3, D4)

Dopamine Receptor

Glutamate Receptor

AMPA, NMDA, kainate

Transmitter-gated ion channel

Mechanism

Opioid Receptor

Antinociception G-protein

coupled receptor Subtype

μ (μ1·μ2), δ(δ1·δ2), κ(κ1·κ2·κ3)

Neuropharmacology

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

Action of addictive drugs

drug 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

Action of addictive drugs

Dopamine-neurotransmitter of CNS

synthesis, storage, release

actions of dopamine Dopaminergic nigro-neostriatal pathway

Mesolimbic dopaminergic pathway

Tubo-infundidular system

Mesolimbic dopaminergic reward system

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

Inhibition of dopamine reuptake

Other drug

ex.cocaine, amphetamine, domperidone

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

Opiates Morphine, heroin endolphin: neurotransmitter released

from brain endolphin opiates → receptor → excite

of periaqueductal gray area → decreased secretion of P substance → decreased pain

Pain pathway

pathway of analgesia suppression

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

nicotinic receptor and its action

Alcohol Disfunction of

recognition (inference,

memory etc)

Influx inhibition of Na+

→ prevention of nerve

system

Decrease of serotonin,

activation of GABA

receptor