pharm autonomic nervous system

Respiratory drugs primarily affect what pathways

efferent pathways - away from the central nervous system (the brain and spinal cord) and toward muscles, organs, or glands to trigger an action

Sympathetic Nervous System (SNS)

“Fight or Flight” stress response

Parasympathetic Nervous System (PNS)

Rest and digest” response

sympathetic division

alpha and beta receptors - norepinephrine

parasympathetic division

muscarinic receptor - acetylcholine

acetylcholine

neurotransmitter—in your body that carries signals between nerve cells and controls muscle movement

norepinephrine

(also called noradrenaline) is a natural chemical that acts as both a stress hormone and a brain messenger (neurotransmitter)

Function of the ANS

Primarily controls physiologic functions that are involuntary

 Heart rate (HR)

 Respiratory rate (RR)

 Bronchial Smooth Muscle

 Blood pressure (BP)

dilate

to become or make something wider, larger, or more open

Neurotransmitters

Chemical messengers that carry signals between neurons (nerve cells) and other cells in the body

 Stored at the nerve terminal (end of the nerve) in a vesicle

 When an impulse is transmitted, the vesicles fuse with the nerve terminal

membrane and released into the synaptic cleft

Adrenergic

Mimics Norepinephrine (NE)

Anticholinergic

Blocks Acetylcholine (ACh)

Four receptors EVERY respiratory therapist must know##

Adrenergic

Drugs that mimic the action of the sympathetic nervous system

 What neurotransmitter is released? norepinephrine

 Sympathomimetic = Adrenergic

 Sympatho: sympathetic nervous system

 Mimetic: Mimic

β-Adrenergic Drugs

Stimulate the β1- and β2-receptors

 Can sometimes stimulate the α-receptors

 What do the α-receptors do?

 Examples of drugs that affect β1-receptors

 Epinephrine

 Ephedrine

 Dopamine

 Dobutamine

β-Blocking Drugs

Block the effects of NE and epinephrine on β1-receptors

 Causes decrease in heart rate and force of contraction

 Extremely useful in clinical practice

 Some affect β1- and β2- receptors

 Propanolol, Nadolol, timolol

 Most commonly used for indications other than hypertension

 Used sparingly for asthmatics… why?

 Some just β1-

 Most commonly used for treating hypertension

m3 receptors

M₃ receptor activation leads to:

 Muscle Contraction

 Bronchoconstriction

 Mucous secretion

 Miserable lungs

At the post-synaptic receptor site, three possible interactions can occur

1. Drugs that stimulate a muscarinic receptor producing a cholinergic

effect

2. Drugs that block ACHE

3. Drugs that block the cholinergic receptors and prevent ACh from

interacting

Most respiratory medications work by either

Stimulating β₂ receptors or Blocking M₃ receptors

Five things you should always remember

1. α₁ stimulation causes vasoconstriction

 Think vasopressors

 2. β₁ stimulation increases heart rate, Explains tachycardia after β-agonists

 3. β₂ stimulation = Bronchodilation, Albuterol, Levalbuterol, Formoterol

4. M₃ blockade = Bronchodilation

 Ipratropium, Tiotropium

 5. If you know the receptor, you can predict both the drug’s effects and adverse effects,The receptor tells the story...