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)
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What drugs are under the category of methylxanthines?

-theophylline in tea
-theobromine in chocolate


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


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


What is the mechanism of THC?

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


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


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


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


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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