Created by: Laura Runstrom and Kim Tran

Muscarinic Receptor Location

M1 M2 M3

• Salivary glands

• Uterus

• Heart• Eyes• Lungs• Stomach• Pancreas

• Lungs• Salivary

glands• Stomach• Eyes• Pancreas• Bladder

The parasympathetic nervous system (PNS) exerts cholinergic effects on the body.

A helpful pneumonic device to help you remember these effects is DUMBELLS.

Throughout the slide show, you will see the highlighted letter accompanying each effect.

Eyes

Constricts pupils for near vision

DUMBELLS

Miosis & Lacrimation

M2 M3

Contraction of sphincter muscle (miosis), contraction of ciliary muscle, lacrimal gland secretion

Heart

Slows down heart to conserve energy

DUMBELLS

Bradycardia

M2>> M3

Heart rate, contractility (atria and ventricle), conduction of AV node

Decrease

Salivary Glands

Increased salivation to aid digestion

DUMBELLSSalivation

M3

Dilation of arterioles, K+ and water secretion

Lungs

Body does not need extra help to

breathe when at rest

M2 = M3

Tracheal and bronchial smooth muscle contraction

Stomach & Intestines

Helps you digest, utilize, and eliminate

your food

DUMBELLS

Defecation

M2,M3

Increase motility and tone,sphincter relaxation, stimulation of

secretion

Urinary Bladder & Ureter

Facilitates voiding

DUMBELLS

Urination

M3 > M2

Contraction of detrusor muscle, relaxation of trigone and sphincter

M1

Possible increase (?) motility and tone of ureter

Uterus

Male Reproductive Organ

M1

Variable relaxation

M3

Erection

Pancreas

Increases pancreatic juices to aid in

digestion

M2,M3

Increase secretion from acini

To review........

The PNS is all about resting, digesting, and conserving energy to fight another day.

Anticholinergics can counteract these effects. To remember anticholingeric side effects, just think “anti-DUMBELLS”.

Anticholinergics can disrupt these functions:

Defecation

Urination

Miosis

Bradycardia

Emesis

Lacrimation

Lethargy

Salivation

ConstipationUrinary Retention

MydriasisTachycardia

No EmesisDry Eyes

Can be ActivatingDry Mouth