Autonomics of Respiration Flashcards
Sympathetic Receptors
- Nicotinic receptors (ACh) –> located on adrenal medulla –> cause actiavtion and release of Epi
- Alpha 1 receptors (Epi=NE»»iso) –> contraction of VSM –> stimulates phospholipase C –> IP3 –> elevated Ca2+
- Beta-2 receptors (iso>Epi»»>NE) –> relaxation of smooth muscle, glycogenolysis (Epi is natural stimulus for B-2 receptors in lung)
Location in body with greatest amount of nicotinic receptors?
Skeletal muscle –> cause contraction
Parasympathetic Receptors
- Nicotinic receptors (ACh) –> located on postsynaptic surface of postganglionic nerve –> causes activation of postganglionic nerve
- Muscarinic receptors (ACh) –> all end-organ responses –> activate PLC or suppress AC
Where do parasympathetic nerves in lung originiate?
Medulla Oblongata
Where do sympathetic nerves to lung originate?
Thoracic Spine
Sympathetics function
constrict vasculature via alpha 1 receptor (decongestants)
dilate bronchioles via beta-2 receptors
Parasympathetics function
constrict bronchioles via muscarinic receptors and increase secretions
(anti-muscarinics dilate bronchioles –> “tropiums”)
Most common initial treatment for asthma?
Albuterol (SABA)
Beta-2 Agonists
All given via inhalation –> restricts activity to lung tissue –> good
Major S.E. = tachycardia and palpitations (beta-1), tremor (beta-2), headache
Epi
- constricts vasculature, relaxes bronchioles
- used for anaphylaxis
- metabolized by MAO, COMT
Iso
- synthetic catecholamine stimulated beta-receptors
- relaxes beta-2 receptors
- metabolizes COMT not MAO
Ephedrine
partial beta-2 agonists (treat bronchospasm)
- releases NE which has direct effects (increase BP, relaxes bronchioles)
Pseudoephedrine
stereoisomer of ephedrine commonly used to treat nasal congestion
Phenylephrine
alpha 1 agonist
Muscarinic receptor antagonists
Ipratropium, tiotropium
bronchodilator and dries up secretions
Phosphodiesterase 4 inhibitor
Roflumilast –> bronchodilator for COPD –> improves FEV1
major side effect –> Nausea
alpha blockers
cause mucosal stuffiness –> block alpha 1 receptors in vasculature
beta blockers
increase airway resistance (bronchoconstriction) –> particularly in asthmatics (olol’s)
Based on efficacy of anatagonists, which of following are likely to cause asthma?
NOT HISTAMINE!!!!
- leukotriene more likely
Zafirlukast effective for asthma, whats causing asthma?
Leukotriene
If diphenhydramine is not effective in asthma, asthma most likely?
Not caused by histamine!!!!
Which is best for treating anaphylaxis
EPI –> constricts vasculature via alpha 1 and relaxes bronchioles via beta-2
Best decongestant?
Alpha 1 agonist –> phenylephrine
Most likely mechnism for beneficial effects of ipratropium in COPD?
bronchodilation (little)
suppressing secretions
