Respiratory Disease Flashcards
In which parts of the autonomic nervous system is ACh found?
pre-ganglionic neurons, post ganglionic parasympathetic + post-ganglionic sympathetic in sweating
released from motor neurons at the NMJ
In Ach an agonist or antagonist?
agonist (affinity + efficacy)
What type of receptor does it activate?
Nicotinic
Muscarinic
What are the effects of ACh transient?
broken down by cholinesterases eg. acetylcholinesterases + butrylcholinesterases
The action of ACh in the respiratory tract mimics the stimulation of which nerve?
vagus
What is airway resistance + what factors contribute to airway resistance in man?
AR = obstruction to airflow
The diameter of the lumen of the bronchioles decreases due to:
- physical means –> cartilage + interseptum junctions of alveoli
- ANS
How many histamine receptor types are there?
4
Where are they located?
H1 = smooth muscle, endothelium + CNS H2 = parietal cells + vascular smooth muscle cells H3 = CNS (+ peripheral NS to lesser extent) H4 = basophils, bone marrow, thymus SI, spleen, colon
What does the H1 receptor do?
bronchoconstriction bronchial smooth muscle contraction vasodilation endothelial separation --> HIVES pain + itching die to insect stings
What physiological and pathophysiological states are the H1 receptors involved in?
allergic rhinitis
motion sickness
sleep
appetite suppression
What does the H2 receptor do?
vasodilation
gastric acid secretion
What does the H3 receptor do?
decreased neurotransmitter release
histamine, acetylcholine, noradrenaline, seretonin
What do H4 receptors do?
chemotaxis
What effect would administration of ACh or autonomic nerve stimulation of airway smooth muscle have on airway resistance? Outline what the graph of this would look like.
Airway resistance would increase
Log curve –> sigmoid shaped
How would adding a muscarinic antagonist affect the shape of this graph + why?
atropine –> competitive –> high dose of agonist to overcome its effects –> graph shifts RIGHT
What side effects would you expect muscarinic antagonists to have?
pupil dilation + blurred vision loss of pupillary reflex tachycardia inhibition of secretions anti-emetic effects
How can you overcome the problems associated with muscarinic antagonists to produce a therapeutically useful drug?
give it locally
modify structure to make it more ionic –> more difficult for it to be absorbed
Ipratropium bromide is a muscarinic antagonist currently used in the treatment of?
COPD + asthma
What type of cell produces histamine in man?
mast cells
Why are histamine antagonists not used for the day-to-day control of asthma?
as histamine is just one of many factors that can constrict the airways
What precursor is involved in the production of leukotrienes?
arachidonic acid
Which leukotrienes are produced in the airways? How do they affect airway resistance?
LTC4/D4/E4
bronchoconstrictors –> increase airway resistance
What strategies can be used in asthmatics to reduce the effects of endogenous leukotrienes?
leukotriene antagonists
drugs that target leukotriene synthesis eg. 5-lipoxygenase blockers
What endogenous compound normally activates beta-2 adrenoreceptors in the airway smooth muscle?
adrenaline
