Week 8 CNS stimulants and drugs of abuse Flashcards Preview

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Flashcards in Week 8 CNS stimulants and drugs of abuse Deck (8)
1

What drugs are under the category of methylxanthines?

-theophylline in tea
-theobromine in chocolate
-caffeine

2

How does caffeine act on the brain?

-adenosine is a neuromodulator that accumulates during fatigue, it binds to receptors in the brain to inhibit the release of NTs to prepare it for rest
-caffeine blocks all types of adenosine receptors which leads to increase firing of neurons and brain activity
-cause the pituitary gland to release hormones like ACTH which prompt adrenal glands to release adrenaline

3

What is the mechanism of LSD (lysergic acid diethyl amide)?

-serotonin agonist at presynaptic receptors in midbrain
-activates sympathetic nervous system
-cause hallucinations and mood alterations
-hallucinations may be rapidly aborted by haldoperidol-antipsychotic agent

4

What is the mechanism of THC?

-binds to cannabinoid receptors (presynaptic CB1) and inhibit release of NT such as glutamate, DA, GABA

5

Classify addictive drugs based on their molecular argot and underlying mechanism of action.

1. Drugs that act via G coupled protein receptors: Opioids, cannabinoids, GHB, hallucinogens
2. Drugs that act via ion channels: nicotine, benzodiazepines, alcohol
3. Drugs that alter MAO neurotransmission: cocaine, amphetamines, ecstasy, bath salts

6

How do addictive drugs alter the mesolimbic dopamine system?

-nicotine: depolarizes DA neurons increasing DA release
-Opioids, GHB: block inhibition of local GABA neurons, increasing DA release
-cocaine, amphetamines: block DAT increasing DA concentration in the synapse
Summary: increase DA concentrations in the target structures of the ventral segmental area (VTA) in the midbrain
-targets of VTA include: nucleus accumbens, prefrontal cortex, amygdala, and lateral hypothalamus
-prolonged stimulation of positive prediction error

7

What are the effects of drug abuse on down stream signaling pathways?

-stimulates deltaFosB, which leads to stable long term changes in neurons by promoting expression of Cdk5 in stratal neurons to promote axon growth and new spine formation
-Cdk5 linked to increase in spine density on target neurons of nuc. accumbens, and prefrontal cortex following chronic cocaine use

8

How is drug induced aberrant neuroplasticity changed by drug withdrawal?

-LTP at VTA dopaminergic neurons remains potentiated even after drug seeking behaviors are extinguished
-over time, depression in synaptic transmission reverses into synaptic potentiation so that behavioral cues previously associated with availability of drug leads to increased efforts to obtain drug
-susceptibility and sensitivity to drug associated sensory cues that lead to intensified drug craving for weeks to months after drug withdrawal

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