Drugs Affecting the Nervous System Flashcards
What is the cortex the location of? (7)
thought, memory, self-awareness, personality, speech, perception of sensation, control of body movement
What is the function of the midbrain?
relax station for cortex, integrates/modulates autonomic functions
What is the function of the brainstem (medulla)?
control area for breathing and cardiovascular control, alertness
What is the function of the cerebellum?
fine motor control, coordinates movement
Each neuron usually releases how many neurotransmitters?
one
T or F: most neurotransmitters are returned to the pre-synaptic nerve terminal and are recycled?
T
How do CNS drugs act?
increase or decrease individual neuronal activity and exert effects by interaction with neurotransmission
What do CNS drugs affect?
NT release, metabolism, and re-uptake
What do the clinical effects of CNS drugs depend on?
localization of neurotransmitters in specific brain areas
List some factors that will impact effect of CNS drugs. (6)
amount released, availability of transport proteins, previous release of NT, degradation of NT in synaptic space, efficiency of re-uptake process, activities of modulating interneurons
What are the 3 major neurotransmitters involved in antidepressant medication?
serotonin, dopamine, norepinephrine
How do antidepressants act?
inhibitors slow the process by which neurotransmitters are reused, resulting in an increased amount of neurotransmitter that are available to stimulate neurons
What are first-line treatment antidepressants? Second? Third?
SSRIs or SRIs: e.g. Celexa, Prozac
SNRIs: e.g. Effexor, Cymbalta
Dopamine re-uptake inhibitors: e.g.Wellbutrin, Zyban
Describe and provide an example for TCAs.
effect on norepinephrine and serotonin, added effect of influencing histamine and acetylcholine
e.g. Remeron
Describe and provide an example(s) for MAOIs.
removes norepinephrine, serotonin and dopamine from the brain
e.g. Nardil, Parnate
Lithium:
function? action? side effects?
mood stabilizer
monovalent cation that can replace Na in some biological cells
tremors, cognitive slowing, hypothyroid, renal insufficiency, leukocytosis, polyuria, polydipsia, coma
*narrow therapeutic window
Anticonvulsants:
function? +/- sedation? ex.?
mood stabilizer
may cause sedation
Valproic acid, Carbamazepine
What do antipsychotics target? AKA? What is the therapeutic goal? ex.?
limbic system and “calming effect”
major tranquillizers
increase dopamine levels in the brain
Olanzapine, Risperidon
What type of drug is used for Alzheimer Dementia? How do these act? Side effects? ex.?
cholinesterase inhibitors
increased acetylcholine levels in the brain in an attempt to increase cognitive function
GI side effects
Donenzepil, Galantamine, Thorazine, Haldol
How do anxiolytics function?
inhibition of the neuron through hyperpolarization: GABA increased chloride conductance, more chloride is able to move into the cell and create a state of hyperpolarization
Benzodiazepines:
function? uses? action? effects? antagonist?
anxiolytic anesthesia induction hyperpolarize neurons amnestic, promote sleep, terminate seizures, augment respiratory depression flumazenil
Barbiturates:
function? uses? risks?
anxiolytic
anesthesia induction (thiopental), hypnotics (pentobarbital), and seizures (phenobarbital)
rapid tolerance, toxic potential, high risk of addiction/abuse
What type of CNS drug is ethyl alcohol? What is the dose that results in respiratory arrest?
nonprescription sedative-hypnotic
400-600 mg/dL
Describe delirium tremens (DTs).
withdrawal effect of CNS hyperactivity (hyperthermia, increased BP, hallucinations, seizures, etc.)
What do analeptic drugs do? What can this be used to treat? ex.?
increase activity of the brain
narcolepsy, ADHD, obesity, depression, AOP
caffeine, aminophylline, doxapram
T or F: analeptic drugs have a clinical role in treating respiratory failure or drug induced respiratory depression?
F
NSAIDS:
function? action? ex.?
analgesic
affect hypothalamus and inhibit production of inflammatory mediators at the pain site
salicylates (aspirin) - antipyretic, analgesic, antiplatelet, increased incidence of Reye’s in children
Acetaminophen (Tylenol) is an example of what? Effects?
nonnarcotic analgesic
effective on mild/moderate pain, may cause lethal hepatic necrosis, OD can be treated with N-acetylcysteine
List and describe 2 naturally occurring opioids.
enkephalins - morphine like neurotransmitter found in the brain and adrenal glands
endorphins - morphine like neurotransmitter found in the brain and pituitary gland
Describe exogenous opioids.
euphoric effect, high doses may cause LOC and respiratory arrest, strong ones are called narcotics
List some examples of exogenous opioid analgesics.
morphine, codeine, fentanyl, heroin, hydrocodone, hydromorphone, oxycodone, tramadol
List some side effects of opioid analgesics.
respiratory depression, constipation, nausea, vomiting, antitussive
T or F: opioid analgesics activate only 1 opioid receptor?
F
What are the 3 opioid receptors?
mu, kappa, delta
Opioid analgesics bind selectively to receptor sites found where?
CNS and GI tract
What types of effects do opioid analgesics produce?
inhibitory
Describe opioid analgesic drugs.
lipid soluble, weak bases, highly protein bound
What is the antagonist to opioid analgesics? Action?
Narcan
occupies opioid receptors and prevent agonist binding
List and describe the different routes of opioid administration.
injection
PCA pumps - keeps control
inhalation - decreases dyspnea, alternative when IV unavailable
Describe combination of analgesic classes.
widely available, separate dosing may prove better with various side effects, toxicities, and half-lives
List some side effects that accompany central sensitization in chronic pain syndromes.
hyperesthesia, hyperpathia, allodynia
What may reduce likelihood of neuropathic problems in chronic pain syndromes?
treatment during acute phase
List some characteristics of neuropathic pain.
evidence of primary injury, pain involving body area with sensory loss, pain characterized as burning, electric, or shooting, dysesthesias in the area, sympathetic hyperactivity, hyperalgesia, hyperpathia, allodynia
PNS:
how many synapses? afferent vs efferent? branches from autonomic neurons?
1
afferent - from skin/muscles/organs to CNS
efferent - from CNS to muscles
sympathetic and parasympathetic
T or F: autonomic system is generally considered an efferent system?
T there are afferent fibres running back to CNS providing feedback about body functions
Where are highly regulated complex function controlled? Where are unrefined, quick reflexes controlled?
brain
spinal cord
How is neural singling both electrical and chemical?
electrical AP signal carried along nerve fibres
at axon terminal, electrical signal causes release of vesicles containing neurotransmitter
chemical signal at synapse
What are the 2 key neurotransmitters involved in neural signalling?
AcH and NE
Define neuroeffector site.
location where nerve interacts with effector organ, gland, or muscle
What is the neurotransmitter associated with the pre and postganglionic fibres in efferent parasympathetic pathways?
ACh
What are the neurotransmitters associated with the pre an postganglionic fibres and adrenal medulla in efferent sympathetic pathways?
pre - ACh
post - NE, ACh
medulla - epi
Where do parasympathetic fibres arise from? Which fibre is short vs long? How do these fibres lie in relation to effector organs?
cranial nerves and sacral portions of spinal cord
pre is long, post is short
lie near or on effector organ
Where do sympathetic fibres arise from? Which. fibre is long vs short? How do these fibres lie in relation to the vertebral column?
thoracic/lumbar regions of spinal cord
pre is short, post is long
lie adjacent to vertebral column
How do ANS drugs work?
mimic or block effect of NT at effector site
What type of effect do parasympathetic neurons provide vs. sympathetic neurons?
para - discrete
sympathetic - broad
Describe cholinergic.
refers to a drug or endogenous molecule (NT) that stimulates ACh receptors
Describe adrenergic.
refers to a drug or endogenous molecule (NT) that stimulates NE receptors
Describe the suffix mimetic vs. lytic
mimetic (‘mimic’) - up regulation
lytic (‘destruction of’) - down regulation
Parasympathomimetic = ? Parasympatholytic = ? Sympathomimetic = ? Sympatholytic = ?
parasympathomimetic = cholinergic parasympatholytic = anti-cholinergic sympathomimetic = adrenergic sympatholytic = anti-adrenergic
Describe parasympathetic effects.
decreased HR/BP/RR, bronchoconstriction, increased secretions, mitosis, increased salivation, increased motility, relaxation of sphincters, increased insulin secretion/energy storage
Where are nicotinic receptors found? What are they?
between pre/post ganglia in both para/sympathetic nervous systems and NMJ
ligand-gated ion channels
What is ACh inactivated by?
cholinesterase
What types of receptors do parasympathetic NT act on?
cholinergic (pre/post), nicotinic, muscarinic (2,3 )
Describe the 3 subtypes of muscarinic receptors that are innervated by the parasympathetic NS. Where else can M receptors be found?
M1 - nasal mucosa
M2 - heart
M3 - a/w smooth muscle
blood vessels
Describe the different acting cholinergic agents.
direct - mimic ACh, methacholine (diagnostic for asthma)
indirect - inhibit cholinesterase enzyme, neostigmine (reversal of non depolarizing muscle relaxants)
cholinesterase reactivate - pralidoxime (tx of organophosphate toxicity)
What is the action of anticholinergic agents? Provide and describe an example.
block ACh receptors
atropine - parasympatholytic agent, competitive antagonist
Describe parasympatholytic (antimuscarinic) effects of atropine.
bronchodilator, prep drying of secretions, antidiarrheal agent, prevention of bed-wetting in children, tx of peptic ulcers/organophosphate poisoning/mushroom ingestions/bradycardia
Describe sympathetic effects.
increased HR/force of contraction/BP/RR, bronchodilation, mydriasis, vasodilation, decreased motility, increased lipolysis and decreased insulin production
What is the adrenergic NT function in SNS? Describe the terminating action of NE.
sympathetic effects at neuroeffector site and systemic effects through action of epi
reuptake process: COMT, MAO (inactivate catecholamines)
Describe the receptors types that are acted upon by the SNS.
a1 (peripheral blood vessels), a2 (auto receptors, CNS), B1 (increased HR/force), B2 (bronchial smooth muscle, cardiac muscle), dopaminergic (similar to epi)
Describe sympathomimetic agents. Provide examples.
stimulate the sympathetic system and produce adrenergic effects
e.g. epi, dextroamphetamine, dopamine, salbutamol
Describe and provide an example for sympatholytic agents.
block adrenergic effects
e.g. propanolol
List all the things involved in neural control of lung function.
a/w smooth muscle/tone, submucosal and surface secretory cells, bronchial epithelium, pulmonary and bronchial blood vessels
Describe direct vs indirect effects in relation to sympathetic innervation.
direct - innervation of nerve fibres
indirect - catecholamine release
List and describe the receptors involved in sympathetic innervation of the a/w smooth muscle.
b2 - mediate relaxation
a - less abundant, minor effect (possible bronchoconstriction)
Describe nonadrenergic, noncholinergic excitatory nerves (NANC).
neither parasympathetic nor sympathetic, causes contraction of smooth a/w muscle
Describe nonadrenergic, noncholinergic inhibitory nerves (NANC).
neither parasympathetic nor sympathetic, causes relaxation of a/w smooth muscle
Which fibre system has been considered as a possible cause of a/w hyperactivity observed in asthmatics?
NANC excitatory C-fibre
