Drug treatment of respiratory conditions

Approximately how many people suffer from a respiratory disease globally?

1/5

What is the most prevelant respiratory condition?

Asthma

Asthma

is a chronic inflammatory disorder of the airways characterized by recurring symptoms such as wheezing, shortness of breath, chest tightness, and coughing. Caused when the airway becomes hyperresponsive to various stimuli.

Afferent Nerves

transmit sensory information from the periphery to the central nervous system.

Efferent Nerves

recieve information from the CNS, regulation of muscle contraction, glands secretion

What are the two receptors common in Afferent nerves?

Chemoreceptors and Nocireceptors are the two main types that detect changes in chemical concentrations and can sense pain, respectively.

What three components are stimulated by efferent nerves?

Parasympathetic Nerves → Bronchoconstriction

Mucus Secretion (Ach binding to M3)

Sympathetic Nerves → regulate production of noradrenaline

What subtype of muscarinic receptors are most prevelant in the respiratory tract?

M3

How is noradrenaline significant for bronchodilation?

Noradrenaline, released by the adrenal glands on the kidneys and is circulated through the blood, binds to adrenic beta 2 receptors which are located in the airway smooth muscle

Inhibatory non-adrenergic non-chollinergic (NANC) Nerves

relax airway smooth muscle

Excitatory non-adrenergic non-chollinergic (NANC) Nerves

causee neuro-inflammation due to tachykinin release (substance P and neurokin A)

Histamine

Receptor → H1

Expressed In → Smooth Muscle

Physiological Effects → Bronchoconstriction

Adrenaline

Receptor → Adrenergic receptors
Expressed In → Smooth muscle
Physiological Effects → Bronchodilation

Cysteinyl Leukotrienes

Receptor → CysLT1 and CysLT2

Expressed in → Mucosa immune cells

Physiological Effects → Bronchoconstriction

Acetylcholine

Receptors → M3

Expressed in → Smooth Muscle

Physiological Effects → Bronchoconstriction

Treatments for Asthma include what?

bronchodilators (relievers) and anti-inflammatories (preventers)

What structural changes occur during asthma?

• Smooth muscle cell contraction

• oedema (buildup of fluid in a part of the body)

• Mucus hypersecretion

• Epithelial damage

• Bronchal hyperreactivity

How is asthma assesed?

Respiratory Function Test. measured using a spirometry calculated using FVC/FEV1

FVC

forced (expiratory) vital capacity. the forced max expiration following full inspiration (<3 sec in healthy condition)

FEV1

Forced expiratory volume in one second. ie the volume of FVC expelled after one second

What readings from a spirometry are considered healthy?

FVC and FEV1 greater than or equal to 80%

FVC/FEVI1 ratio (should be >0.7)

What two things can anti-asthmatic drugs target?

Ones that target bronchoconstriction and ones that target inflammation

How do bronchodilators work

promoting smooth muscle relaxation by stimulating beta-adrenoreceptors or their 2nd messengers or by blocking and constricting cholinergic effects

Beta-2 agonists

Salbutamol and Terbutaline. Both are short acting beta 2 agonists

Muscarinic Antagonists

Ipratropium. Short acting

Methylxanthines

Theophylline and aminophylline

Agonists vs antagonists

Agonists stimulate receptor activity, while antagonists block or inhibit it, leading to opposing effects on respiratory function.

Glucocortoids

main drugs used for anti-inflammatory action in asthma. Block the progression of chronic asthma

How do glucocorticoids work?

Inhibit the production of prostanoids, leukotrienes, and cytokines

Decrease release of cytokines particullary those released by th2 lympocytes

How are glucocortoids administered

Inhaler. frequently paired with a beta 2 adrenoreceptor agonist

Main types of glucocortoids

beclomethasone and fluticasone (high potency)