CNS Pharmacology II: Stimulants & Depressants Flashcards
What is a Psychoactive / Psychotropic drug?
Drugs that affects mood and behaviour
Which neurotransmitters are Amphetamines structurally similar to?
Dopamine & Noradrenaline
What are THREE ways in which Amphetamines increase DA and NA transmission?
- Increase secretion of DA and NA
- Compete with DA and NA degradative enzymes
- Competing with DA and NA re-uptake systems
Which neurons are mainly stimulated by amphetamines?
Noradrenergic neurons of the ANS
What FOUR ways do amphetamines act on Dopamine (DA) synapses?
- Compete with DA uptake carrier
- Compete with DA uptake into synaptic vesicles
- Inhibit DA degradation (at higher conc. via MAO)
- Bind to DA re-uptake transporter, causing it to act in reverse and transport free DA out of the nerve terminal
What TWO ways do amphetamines act on Noradrenaline (NA) synapses?
- Increase release of NA into synaptic cleft
- Inhibit NA re-uptake transporter
What are the FOUR Dopamine pathways in the brain?
- Nigrostriatal Pathway
- Mesolimbic Pathway
- Mesocortical Pathway
- Tuberoinfundibular
Which areas of the brain, known as the Reward Pathway, do drugs of abuse modify the action of DA in?
- Ventral Tegemental Area (VTA)
- Nucleus Accumbens
Which receptor in the CNS is Nicotine an agonist for?
Nicotinic Acetylcholine Receptor (nACh)
What does ACh release in DA neurons cause?
INCREASED DA release
Which nACh receptor is believed to be linked with addiction?
a4β2
What is the mechanism of action of Cocaine on DA or NA neurons?
- Cocaine binds to DA and NA re-uptake transporters, which inhibits DA and NA removal from synaptic cleft and degradation by MAO
- DA and NA remain in synaptic cleft activating the post-synaptic receptors and enhancing neurotransmission
What are TWO examples of Methylxanthines?
- Caffeine
- Theophylline
Which neurotransmitter are Methylxanthines structurally similar to?
Adenosine
* Inhibitory NT
How do Caffeine and Theophylline act on Adenosine receptors?
Non-Selective Antagonists of the A1 and A2 receptors