General Drugs Flashcards
What is inflammation?
A complex biological response to harmful stimuli such as trauma or infection
It is normally beneficial and is key to physiological processes such as tissue repair and regeneration
When it becomes chronic, can cause problems
What are the major classes of anti-inflammatory drugs?
NSAIDs (aspirin and ibuprofen)
Glucocorticoids
What immune cells are important for inflammation resolution and regeneration?
Neutrophils undergo opotosis during inflammation and then are rapidly cleared by macrophages- termed efferocytosis
After clearing neutrophils, macrophages change phenotype from pro to anti inflammatory
What does effercytosis lead to?
Efferocytosis helps contribute to tissue repair and resolution however dysregulated efferocytosis can lead to permanent tissue damage.
What drugs act on neutrophils to cause apoptosis?
CDKi
Cyclin-dependant kinase inhibitors
Stop chronic inflammation as if there to too many neutrophil this causes a ,assive influx of inflammatory molecules and chronic inflammation
What is a current theory regarding efferocytosis and tissue resolution?
Driving neutrophils into apoptosis will result in faster resolution of the tissue
What is the mechanism of action of CDKis?
Cyclin-dependent kinase inhibitors inhibit the production of Mcl-1, a key protein involved in inhibiting apoptosis
This induces granulocyte (neutrophil, eosinophil) apoptosis and enhances resolution of granulocyte-dependent inflammation
What is a CDK inhibitor currently being trialled?
R-roscovitine
What are survival agents of neutrophils?
GM-CSF and LPS, both mediators of inflammation
How does R-Roscovitine affect GM-CSF and LPS treated neutrophils?
It inhibits the delay of apoptosis induced by these survival agents
I.e. it overrides pro-inflammatory factors
What did Rossi et al 2006 discover about R-roscovitine?
R-roscovitine enhances the resolution of established neutrophilic-dependent inflammation of acute pleurisy via a caspase dependent mechanism
Carrageenan was given intrapleurally which is a plant that causes inflammation
How can it be established that a drug is acting in a caspase dependent mechanism?
Give a caspase inhibitor i.e. zFAD and see if the drugs still produces effects
What is ARDS?
Acute respiratory distress syndrome
There is no current pharmacological therapy despite many trials and mortality is > 25%
In ARDS, fluid builds up inside the tiny air sacs of the lungs, and surfactant breaks down. Causes less oxygen transfer through the lungs
Would could potentially be used to treat ARDS?
CDK inhibitor
AT7519 was a potent inducer of neutrophil apoptosis and and resolution occured quicker in a mammalian model of lung inury
What did AT7519 do to established E coli induced lung infection?
Accelerated the resolution of established E coli induced lung inflammation
Decreased neutrophil survival
Less E coli present after treatment- counterintuitive but hypothesised that macrophages are better at removing bugs than neutrophils
What happens to the airway of Mcl-1 overexpressing mice?
Exacerbated allergic airway inflammation
Due to its protective effect stopping eosinophils from apoptosis
How do glucocorticoids promote the clearance of granulocytes?
Via MER
MER deficient mice have a enhanced inflammatory response
Why are zebrafish useful for experiments?
They can be genetically manipulated
Do not need a home license to handle
They have an intact immune system
Transparent so can visualise the proccesses occuring within them
How long are you allowed to use zebrafish for before you need a license?
Allowed to use zebrafish for 5 days after fertilisation
How can the immune system be studied in zebrafish?
Can study the immune response via dyed cells through transgenic lines
If you cut off the tail it starts to regenerate and immune cells can be visualised
What did transgenic staining reveal about the injuries in zebrafish?
Injury of the zebrafish tailfind results in recruitment of neutrophils and macrophages to the injury site
Macrophages eventually dominated at the injury site
What is wogonin?
A CDKi
What does wogonin do in zebrafish inflammation?
- It was found by lucus et al 2013 that wogonin (a CDKi) enhances resolution of established inflammation in zebrafish
- Number of neutrophils decreased in the presence of wogonin
What did the Rossi group find about macrophages in zebrafish tailfin regeneration and repair?
KO of Irf8 lead to the generation of no macrophages. In the absence of macrophages there is reduced regeneration
What are the different types of pain?
Nociceptive pain- pain caused in response to a noxious substance
Neuropathic pain- pain caused by disease within the PNS or CNS
Both types of pain can coexists
What does paracetamol do do oesteoarthritis?
It was found that in elderly patients with OA, they experianced less intense pain with paracetemol
Functional MRI studies found the pain was localised to smaller area due to the activation of neurones in sensory cortex
What is neuropathic pain?
Ongoing, unremitting pain or either peripheral or central origin
Due to nerve injury
Difficult to treat
What may cause neuropathic pain?
Stroke- causes extra electrical activity and firing
Lesions within the spinal cord
What is phantom limb syndrome?
Post amputation pain in the missing limb.
There is an abnormal expression of ion channels that causes spontaneous firing in the injured or severed nerves
How can phantom limb syndrome be treated?
Local anaesthetics can influence the firing rate of the damaged nerves by blocking Na+ channels
Systemic anaesthetics cannot be given due to effects on muscles and heart
Whar is nocioception?
The sensory nervous system’s process of encoding noxious stimuli
Where do cell bodies of sensory neurones lie?
The dorsal root ganglion
What is referred pain?
Referred pain is pain perceived at a location other than the site of the painful stimulus It is the result of a network of interconnecting sensory nerves, that supplies many different tissues
E.g. organ pain can radiate to the skin and this makes diagnosis harder
What receptor is present within sensory neurones and how could these be used to treat pain?
NaV 1.7, 1.8, 1.9
If these could be selectively blocked, could stop pain firing to the dorsal root ganglion
Systemically blocking Na+ receptors would have systemic effects
What can happen to nociceptor Na+ channels following an injury?
Can accumulate subtype specific sodium channels
Also get a build up of clusters of these channels near the axon which may trigger the neurone to activate more readily
How is pain mapped within the brain?
The somatosensory cortex is a map of body
Pain awareness comes from the anterior cingulate cortex, insula and amygdala
How does synaptic plasticity change in chronic pain?
In short nociceptor activation, there is AMPA discharge but NMDAR are still blocked by Mg2+
After repetitive firing there is more Glutamate released, more AMPA activation and NMDA activation so more excitability and magnification of the pain
What limits the synpatic plasticity that occurs in pain?
Ketamine
NMDAR antagonist
Limitations to its use due to psychotropic inducing effects
What are MAGUK proteins?
Membrane associated gyuanylate kinase (MAGUK) proteins are scaffolding proteins that tether NMDA receptors
What is an example of a NMDA scaffolding protein?
PSD-95
Huge scaffold molecules- can hold onto many NMDA receptors and attach them to the synapse. Makes sure there are many receptors available for ligand
How are scaffolding molecules involved in pain?
When PSD-95 is deleted in mice, hypersensitive pain behviours are stoping
Therefore pain may relate to signalling molecules not just receptors
What are the main targets for opiod receptors?
μ-opioid receptor, mu OR; δ-opioid receptor, deltaOR; and κ-opioid receptor, kappa OR