L16 Pharmacology of Respiratory Tract Flashcards
describe how SM contracts
stimulus –> Ca++ release –> Myosin +P –> thin filament/ thick filament engagement –> contraction (lattice collapse)
Describe how SM relaxes
stimulus withdrawal –> Ca++ uptake SR –> Myosin loses P –> thin filament/ thick filament disengagement –> relaxation (lattice normal shape)
What is the key messenger that helps to phosphorylate myosin?
cAMP (adds/removes Ca++)
What action does B2 agonists have on bronchioles
inc cAMP > inc protein kinase > inactivation MLCK > removal Ca++ > bronochodilation
increase of MCC
What are side effects of B2 agonsists
high doses might also target B1 so will see tachycardia, excitement, sweating
What is an example of a B2 agonist
Clenbuterol
What action do phosphodiesterase inhibitors have on bronchioles?
prevents the degradation of cAMP so > inactivates MLCK > BRONCHODILATION
- Inc HR & CO
- CNS stimulation
What are more effective, B agonists of phosphodiesterase inhibitors
B agonist
What are some effects phosphodiesterase inhibitors
CNS stimulation
diuresis
What is an example of a phosphodiesterase inhibitor
Theophylline
What action do muscarinic receptor antagonists have on bronchioles?
Parasympathetic stimulation causing bronchoconstriction via the M3 muscarinic receptors on bronchial SMs.
Airway relaxation
What has a more profound affect, B2 adrenergic agonists or muscarinic receptor antagonists (anticholinergics)
B2 !
Corticosteroids are what type of drug?
anti-inflammatory
repress expression of proteins controlling immunomodulatory genes that are elevated in asthma sufferers.
What is the best route of delivery for these drugs?
inhalation Generaly b/c more localised effects
what is the action of mucolytics
increase production of serious mucus in resp tract to make mucus thinner and less viscous to assist MCC
What are antitussives and what are 2 examples
cough suppressants
- opioids
- antihistamines
