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22 terms

Pharmacology Week 4

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What's the difference between CNS and PNS?
CNS involves the brain and spinal cord, while PNS involves everything else but the brain and spinal cord... like sensory and motor neurons.
What's the difference between somatic and autonomic?
They are both subsets of the PNS. Somatic system covers all voluntary actions, i.e. input from the sense organs and output to skeletal muscles. Autonomic covers all involuntary actions, meaning input from internal receptors and output to smooth muscles and glands
Neurotransmitter for Sympathetic nervous system.
noradrenaline, why it is known as "Adrenergic nervous system"
Neurotransmitter for Parasympathetic nervous system.
acetalcholine, why it is known as "Cholinergic nervous system."
In The parasympathetic nervous system, where do neurons emerge from in the CNS?
from the cranial and sacral areas of the spinal cord
In the sympathetic nervous system, where do neurons emerge from in the CNS?
from the thoracic and lumbar areas of the spinal cord.
What are some functions of cholinergic agonists?
Treat atonic bladder (a large dilated bladder that does not release urine due to a lack of innervation or something else), xerostomia (dry mouth due to lack of saliva, can be from radiation therapy), sjogren's syndrome (Autoimmune disorder in which immune cells attack and destroy exocrine glands that produce tears and saliva), Myasthenia gravis (autoimmune disorder which causes antibodies to block acetalcholine receptors), eaton-lambert syndrome
what is eaton-lambert syndrome?
a rare autoimmune disorder which inhibits voltage gated calcium channels on the presynaptic membrane of the neuromuscular junction, preventing acetalcholine from being released, so muscles do not contract. cholinergic agonists help to treat this syndrome.
describe cholinergic agonists
They increase the postsynaptic stimulation of a cholinergic neuron, act like acetylcholine but have longer durations of action (these are direct cholinergic agonists), not broken down by acetylcholinasterase and thus have a much longer duration of effect, indirect cholinergic agonists do not bind to the acetylcholine receptors but instead cause the release of endogenous substances.
adverse drug reactions of cholinergic agonists.
headaache, urinary urgency, nausea, miosis, diaphoresis, hypotension, salivation, flushing, abdominal pain and cramps, bronchospasm, diarrhea, SOB (ER visit would be if bronchospasm)
reversible anticholinasterases
prevent cholinasterase from breaking acetalcholine down, so it stays in the cleft for longer and causes increased stimulation of the postsynaptic membrane receptors
How do anticholinergics affect gastric motility?
They can inhibit gastric motility and can affect absorption of the drugs.
antimuscarinic agents
inhibit parasympathetic functions. antispasmodic (relaxes GI tract and bladder), treats Parkinson's, extrapyramidal symptoms from other drugs, antitussive, lung and nasal congestion, overactive bladder and urinary incontinecne, motion sickness, as an antiemetic
what are extrapyramidal symptoms?
dyskinesias (movement disorders associated with the use of antipsychotics including repetitive/involuntary/purposeless body movements like tongue thrusts and eye blinking)
antimuscarinic agents aka muscarinic receptor antagonists function
act by binding to post-synaptic receptor sites and preventing binding of Ach to these receptors in the parasympathetic division of the autonomic nervous system
ADR's of antimuscarinic agents
blurry vision, confusion, drowsiness, mydriasis (excessive dilation of the pupils), constipation, dry mouth, tachycardia, restlessness, headache, urinary retention
What are the three main concerns about absorption with regard to drug-herb interactions?
pH: usually it takes a very acidic environment in the gut for drugs to be absorbed, gastric motility (need a rather slow peristalsis to give enough time for drugs to be absorbed)
How do some antidepressants and antipsychotics affect digestion?
Can inhibit peristalsis, causing constipation
How do herbs like E jiao and other gelatin based herbs affect the absorption of drugs
Drugs taken 2 hours before or four hours after these particular herbs will not be absorbed well because they are cloying and sticky and impede digestion
Describe distribution's role in drug-herb interactions and how protein binding affects drug-herb interactions
A drug or herb with the majority ofits active ingredients being highly protein bound are very susceptible to interactions
What are some drugs that are highly protein bound and thus more susceptible to drug-herb interactions?
Warfarin, phenytoin, oral contraceptive pills, and non-steroidal anti-inflammatory drugs (NSAIDS)
Describe metabolism's role in drug herb interactions
One of the biggest targets of interactions within this realm is the cytochrome P450 system, which can be inhibited or promoted by some substances