Drug_Addiction_Flashcards
Describe the main brain areas involved in drug reward and their functions in the circuit
The main brain areas involved in drug reward include the ventral tegmental area (VTA), nucleus accumbens (NAc), prefrontal cortex (PFC), and the extended amygdala. The VTA releases dopamine into the NAc, which reinforces drug taking and seeking behaviors. The PFC is involved in decision-making and exerting control over drug use. The extended amygdala is associated with the negative emotional states experienced during withdrawal.
Describe the main common effect of drugs of abuse on neurotransmitters
The common effect of drugs of abuse is to increase dopamine release in the nucleus accumbens, which enhances the rewarding effects of the drug. Different drugs achieve this through various mechanisms but ultimately elevate dopamine levels, reinforcing drug use and leading to potential addiction.
Describe how the focus changes in the reward circuit in progression from acute effects to addiction
Initially, drug use increases dopamine release, reinforcing use due to immediate rewarding effects. Over time, chronic use changes the brain’s reward system, reducing its responsiveness to normal rewards and increasing sensitivity to drug-related cues. This shift leads to a pathological focus on seeking the drug over other healthy rewards, facilitating addiction.
Describe how stimulant drugs elevate dopamine levels
Stimulant drugs such as cocaine and amphetamines increase dopamine levels by blocking the dopamine transporter (DAT), which inhibits the reuptake of dopamine into neurons, leading to an accumulation in the synaptic cleft and increased activation of dopamine receptors.
Describe how alcohol and opioids elevate dopamine levels
Alcohol increases dopamine by disinhibiting the dopaminergic VTA neurons via GABA interneuron inhibition, which indirectly enhances dopamine release. Opioids increase dopamine release in the same fashion, stimulating mu opioid endorphin receptors on the interneurons.
Name one example of non-dopamine reward mechanism (neurotransmitter change)
One example of a non-dopamine reward mechanism is the endocannabinoid system, which can modulate neurotransmitter systems like GABA, glutamate, and dopamine, influencing reward processing through mechanisms separate from dopamine.
Define positive and negative reinforcement
Positive reinforcement involves increasing a behavior by presenting a rewarding stimulus after the behavior, while negative reinforcement involves increasing a behavior by removing an aversive stimulus in response to the behavior. Both are used to increase the likelihood of a behavior’s occurrence.
