Lecture 36 - mechanisms of addiction

Question 1

describe the reward pathway

Answer 1

VTA
DA of Medial forebrain bundle
NA
Prefrontal Cortex/Cortical/Limbic systems

Behavioral changes

Question 2

molecular changes in addiction

Answer 2

CREB
cAMP 
gene transcription
changes to cell function
Neural plasticity

Question 3

Cocaine –
Sites of action
Mechanism

Answer 3

Binding Sites – Caudate Nucleus, VTA and NA

Mechanism – DA reuptake transporters antagonist

Question 4

Amphetamine/Methamphetamine –

Mechanism

Answer 4

taken up into the synapse via the DA transporters

Bind at the VMA, block vesicles from filling with DA

DA concentration overloads the synapse

Reverses the action of the DA reuptake transporters

Question 5

Opiates
Locations of activity
mechanism

Answer 5

thalamus, VTA, NA – euphoria

Cortical regions – mediate the analgesia and sedation

Three-way in the VTA/Nucleus Accumbens
Inhibit GABA release (which is tonically inhibiting DA release)
therefore increases DA release

Question 6

Marijuana

what is the endogenous ligand to the cannabinoid receptor?

mechanism of action

Answer 6

Anandamide

Mechanism – The three-way;

THC mediated decrease in Tonic GABA inhibition

Increasing DA release

Question 7

nicotine –

mechanism

Answer 7

Binds N ACH receptors on the DA neurons; inducing DA release
Binds with higher affinity than ACH
Increases DA releases