Drugs of abuse I Flashcards
What are the two qualities of dependence?
- Development of tolerance
2. Withdrawal symptoms
How does tolerance come about?
- Decrease in amount of available drug
2. Changes of drug receptor action
What is addiction?
Relapsing drug use despite negative consequences
What is the dopamine hypothesis of addiction?
All addictive drugs target the mesolimbic dopamine system in the VTA
What is the role of the ventral tegmental area in addiction?
Dopamine neurons in this area project to several brain receptors involved in reward processing
What are the two parts to drug abuse?
- get euphoria/reward
2. Detrimental to health
What is the hallmark of drug addiction?
Compulsive drug use
What is pharmacokinetic tolerance?
Increased drug metabolism or amount of drug availability
What is pharmacodynamic tolerance?
Desensitization and/or downregulation of receptors
What are the areas in the brain that the VTA projects neurons to in the reward pathway? (4)
Nucleus accumbens
Amygdala
Hippocampus
Prefrontal cortex
What is the general principle with withdrawal ssx?
Opposite of the drugs taken
What is “psychological dependence”? “Physiological dependence”?
Psychological = Addiction Physiological = dependence
What is the scale used for the relative risk of addiction?
1 through 5, with 1 being non-addictive and 5 being highly addictive
What are the three MOAs of increased dopamine release in the reward pathway via addictive drugs?
- Activation of Gi
- Activation of ionotropic receptors
- Targeting dopamine transporter
What does activation of Gi do in the dopaminergic neurons of the reward pathway do, and how does this lead to increased reward?
Inhibits the firing of the inhibitory interneurons on Dopaminergic neurons
What does activation of ionotropic receptors do in the dopaminergic neurons of the reward pathway do, and how does this lead to increased reward?
Enhances release of dopamine in activation of GABAergic neurons
What does targeting of dopamine transporter do in the dopaminergic neurons of the reward pathway do, and how does this lead to increased reward?
Blocks dopamine reuptake, leading to increased dopamine in the synapse
What is the MOA of opioids in generating reward pathway stimulation?
Activate Gi/GABA on inhibitory interneurons
What is the MOA of THC in generating reward pathway stimulation?
Activate Gi/GABA on inhibitory interneurons
What is the MOA of cocaine in generating reward pathway stimulation?
Block dopamine reuptake
What is the MOA of amphetamine in generating reward pathway stimulation?
Block dopamine reuptake and cause release of dopamine from vesicles
What is the MOA of nicotine in generating reward pathway stimulation?
Activates ion receptors to increase release of dopamine