CNS Pharmacology Flashcards
Major function of CNS
Processing info and generating the appropriate response
Name the excitatory CNS Neurotransmitters
Acetylcholine
Dopamine
Glutamate (Most abundant)
(Nor)epinephrine
Name the inhibitory CNS neurotransmitters
Gamma-aminobutyric acid
Serotonin
Drug classes causing CNS depression (incr inhibition, decr excitation)
(From lowest effect to greatest) Anesthetics (general) Narcotics Hypnotics Sedatives Tranquilizers
Drug classes causing CNS stimulation (incr excitation, decr inhibition)
(From lowest effect to greatest)
Analeptics
Psychomotor Stimulants
Convulsants
The balance between excitation and inhibition in the brain can mean life or death? True or False
True
What is the process of CNS excitability by Glutamate?
When GLU activates the NMDA receptor > influx of Ca + Na > excitation
What is the mechanism of GABA inhibitory effect on neurons?
When you activate GABA a receptor > influx of Cl > decr ability of cell to respond/dampens cell’s activity
What is going on neurologically with a seizure?
Excessive and abnormal brain cell activity arising from too much excitation or too little inhibition
What is the mechanism of action of anti-convulsants?
Acts to limit the initiation or spread of a seizure by working to enhance GABA > reduces excitability of the neurons
Phenobarbital
Barbiturate
Acts as anticonvulsant at doses below those that produce anesthesia
What are the general effects of tranquilizers-sedatives?
They often work synonymously to decrease anxiety and produce a mild sense of drowsiness; calming effect or chemical restraint
What are the classes of tranquilizers-sedatives?
Phenothiazine, butyrophenone, and benzodiazepines (GABA)
- acepromazine
- diazepam
- midazolam
What are hypnotic sedatives?
Agents that produce calm (sedative) and sleep (hypnosis); dose-dependent spectrum of sleep, CNS depression, and sedation ; NOT anesthesia
Uses of Narcotics
Induces deep sleep; drug class = morphine
- patients cannot be easily aroused from sleep
What does it mean that the effects of CNS depressants can be additive or synergistic?
This may cause global depression of critical CNS functions (e.g. Alertness, breathing, CV control) and lead to unexpected coma and/or death
Adrenaline’s function
Fight or flight NT
Function of Norepinephrine
Concentration NT
Dopamine’s function
Pleasure NT
Serotonin’s function
Mood NT
GABA’s function
Calming NT
Acetylcholine’s function
Learning NT
Glutamate’s function
Memory NT
Endorphin’s function
Euphoria NT
What NTs are classified as monoamines (biogenetic amines)?
Epinephrine Norepinephrine Dopamine Histamine Serotonin
What NTs are classified as amino acids & derivatives?
Aspartate
Glycine
GABA
Glutamate
What NTs are classified as neuropeptides?
ACTH Endorphins Somatostatin Aldosterone Enkephalins TRH
What are monoamines?
Substances that act as peripheral transmitters as well as those that act almost entirely within the CNS (dopamine)
- synthesis, release, and elimination mechanisms in CNS are identical to peripheral neurons
- DO NOT CROSS BBB
- broken down by MOA
What is the biosynthetic precursor of dopamine, EPI, and NE? Elimination method?
L-tyrosine; uptake or MAO
What is the biosynthetic precursor of Histamine? Elimination method?
L-histadine; HMT
What is the biosynthetic precursor of Serotonin? Elimination method?
L-tryptophan; uptake or MAO
Define catecholamine
- generally considered to be excitatory transmitters (esp. NE and DA) for most brain functions
- drugs may activate or block receptors
What is an example of a catecholamine used therapeutically?
Imipramine- inhibitor of CA + uptake (NE, EP, DA)
- used for narcolepsy, cataplexy (stimulates arousal)
What is an example of a monoamine oxidase inhibitor?
Selegiline - used to treat canine cognitive dysfunction
What are the effects of acetylcholine antagonists on CNS?
CNS depression, delirium, short-term memory loss
Define serotonin (5-HT)
- synthesized from L-tryptophan
- eliminated similar to CA > degraded by MAO and uptake by 5-HT transporters
- many 5-HT receptors
- effects: regulation of mood, appetite, sleep/wake cycles, sensory perception
Examples of serotonin therapeutic agent
Fluoxetine: SSRI
Used for OCD, aggression
- clomipramine: NERI & SSRI
- used for separation anxiety
What are the effects of serotonin syndrome?
High body temp, tachycardia, diarrhea, and agitation
What are the CNS effects of GABA agonists?
CNS depression
GABA antagonists cause what CNS effects?
CNS Excitation
Examples of GABA Therapeutic agents
-Barbiturates: GABA agonists
Uses: sedation, euthanasia
-Benzodiazepines: GABA agonist
Uses; anxiety, sedation
Other examples of Catecholamine Therapeutic agents:
Acepromazine: DA antagonist Uses: sedative - Reserpine: destroys CA vesicles Uses: sedative (works well in horses) -Xylazine: alpha2 agonist Uses: sedative/analgesic
Drugs that block excitatory amino acids (EAAs) have what effects?
Decreased excitation or inhibition
Example of an EAA Therapeutic Agent
Ketamine: NMDA receptor
Dissociative anesthetic
Drugs in the same Rx class can have marked differences in ability to cross BBB? True or False?
True
