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Neuro Unit 5: How do our choices change our brains?. Unit 5.2: Drugs of abuse alter synaptic transmission. Do Now:. Addictive drugs increase synaptic transmission in the reward pathway. Brainstorms ways that drugs could increase synaptic signaling. . The Brain’s Reward Circuit. - PowerPoint PPT Presentation
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Neuro Unit 5: How do our choices change our brains?
Unit 5.2: Drugs of abuse alter synaptic transmission
Do Now:
• Addictive drugs increase synaptic transmission in the reward pathway. Brainstorms ways that drugs could increase synaptic signaling.
The Brain’s Reward CircuitHuman Brain Rat Brain
VTANAc
PFC
The Brain’s Reward Circuit
VTA
NAc
Prefrontal Cortex
Synaptic Transmission
Ca2+
1. Action Potential in VTA
2. Voltage-gated Ca2+
channels open. Ca2+ flows into cell
4. Dopamine binds to postsynaptic receptors.
5. Ion channels open on postsynaptic membrane,
allowing ions to flow into cell.
6. Excess dopamine is pumped back into presynaptic cell.
3. Ca2+ sensitive proteins fuse synaptic vesicles to
membrane, releasing dopamine into synaptic cleft
Dopamine
How do drugs of abuse alter synaptic transmission???
VTA
NAc
Prefrontal Cortex
Inhibitory Neuron
The Reward Pathway
VTA
NAc
Prefrontal Cortex
Inhibitory Neuron
Cocaine & Amphetamines
NicotineMarijuana
AlcoholHeroin & Morphine
Heroin & Morphine
Ca2+
Dopamine
Inhibitory Interneuron
AlcoholHeroin & Morphine
Ca2+
Dopamine
Inhibitory Interneuron VTA
Nicotine &Marijuana
Ca2+
Dopamine
VTA NAc
Cocaine & Amphetamines
Heroin & Morphine
Drug
Site of action in reward pathway
Drug Target (Receptor, Reuptake
pump, etc.)
Effect on VTA action potentials
Effect of dopamine
release and/or dopamine
Effect on NAc action
potentials
Cocaine VTA Dopamine reuptake pump
None Increase dopamine levels
Increase
Amphetamine VTA Dopamine reuptake pump
None Increase dopamine levels
Increase
Nicotine VTA Nicotinic receptors
Increase Increase dopamine release & levels
Increase
Alcohol Inhibitory interneuron
GABA receptors
Increase Increase dopamine release & levels
Increase
Heroin & Morphine
Inhibitory interneuron & NAc
Opiate receptors
Increase Increase dopamine release & levels
Increase
Marijuana VTA Cannabinoid receptors
Increase Increase dopamine release & levels
Increase
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