CNS Drugs Flashcards
What is the receptor for glutamate? What is the mechanism?
NMDA
- excitatory
- increase Na+ Ca++ K+ ion ch. conductance
What is the receptor for GABA? What is the mechanism?
GABAa and GABAb
- inhibitory (more -ve inside)
- GABAa: incr. Cl- conductance
- GABAb: incr. K+ conductance
What is the receptor for dopamine? What is the mechanism?
D2
- inhibitory (decr. cAMP)
- Presynaptic: incr. K+ conductance
- Postsynaptic: decr. Ca++ conductance
What is the receptor for serotonin? What is the mechanism?
5-HT
- 5HT2a: excitatory - incr. IP3 & DAG
- 5HT1a: inhibitory - decr. cAMP
What is the receptor for opioids?
mu
- opioids are mu agonists
- naloxone is a mu aNTAGonist
What is the receptor for cannabinoids? What is the mechanism?
CNS: CB1
PNS: CB2
- inhibit GABA and glutamate release
What is the receptor for acetylcholine? What is the mechanism?
M1, M3, M5 M2, M4 N - cholinergic (PSNS) receptors - incr. IP3 & DAG conductance; decr. K+ conductance - decr. cAMP conductance
What is the receptor for norepinephrine? What is the mechanism?
in the CNS a1, a2, b1, b2 - adrenergic (SNS) receptors - incr. IP3 & DAG conductance; decr. K+ conductance - decr. cAMP (inhibitory) - incr. cAMP
What is the mechanism of action of L-DOPA?
- increase dopamine synthesis
What is the mechanism of action Ropinerole?
- D2 receptors
- receptor agonist (parkinsons = too little dopamine)
- treats ms. stiffness and tremors
What is the mechanism of action of Selegiline?
- inhibit MAO-B
- MAO-B metabolizes MPTP to toxic MPP+ (dopamine breakdown)
What is the mechanism of action of Benztropine?
- anti-muscarinic
- block ACh to balance low dopamine levels
- prevents sweating, muscle stiffness, and constriction of smooth muscles
What is the mechanism of action of Cocaine?
- incr. dopamine transmission
- prevent reuptake of dopamine
- drug induced psychosis –> schiz.
(also prevents reuptake of serotonin and NE) - drug of abuse
What is the mechanism of action of Amphetamine?
- incr. dopamine transmission
- incr. release of dopamine
- drug induced psychosis –> schiz.
(also incr. release of NE and serotonin) - drug of abuse
What is the mechanism of action of PCP?
- NMDA receptor aNTAGgonist (glutamate)
- hallucinogen: visual illusions and perceptual distortions
- drug of abuse
- Adverse: panic rxn, psychosis, flashbacks
- OD is fatal
(glutamate and serotonin imbalance = psychosis)
What is the mechanism of action of LSD?
- 5HT2A receptor agonist (serotonin)
- hallucinogen: visual illusions and perceptual distortions
- drug of abuse
- Adverse: panic rxn, psychosis, flashbacks
- OD causes strong uterine contractions
(glutamate and serotonin imbalance = psychosis)
What is the mechanism of action of Haloperidol?
- D2 receptor aNTAgonist > 5HT2a aNTAgonist
- anti-psychotic
- butyrophene derivative
- action: to decr. dopamine activity (that causes psychosis in limbic)
What is the mechanism of action of Olanzapine
- 5HT2a aNTAGonist > D2 aNTAGonist
- newer anti-psychotic
- atypical drug
- action:
- decr. dopamine activity in limbic
- incr. dopamine in cortex
- incr. glutamate in cortex
What is the glutamate hypothesis?
- decr. glutamate function = NMDA aNTAGonists
induces psychosis/hallucinations - decr. glutamate = incr. dopamine (limbic) = psychosis (+ve)
- decr. glutamate = decr. dopamine (cortex) = -ve symptoms
What are the adverse effects of anti-psychotics?
CNS
- parkinson’s like symptoms (D2 is aNTAGonized in striatum)
- hormal/metabolic dysfunction (D2 aNTAGonized in diencephalon)
- sedation H1 and a1 receptors aNTAGonized
ANS
- a1 aNTAgonized = hypotension (low BP)
- M aNTAgonized = anti-muscarinic = atropine like effects (dry mouth, constipation - inhibit gland secretion and sm. ms. mvts)
