Neurotransmitter Receptor
Locations
Acetylcholine
Muscarinic -Parasympathetic targets
Cholinergic
-Heart
Acetylcholine
Cholinergic
Nicotinic
Norepinephrine
Adrenergic
Norepinephrine
Adrenergic
Norepinephrine
Adrenergic
Alpha 1
Norepinephrine
Adrenergic
Beta 2
Alpha 2
Beta 1
-Released from postganglionic
neurons to stimulate skeletal
muscle
-Ganglia and adrenal medulla
All sympathetic targets except
heart
Presynaptic adrenergic nerve
terminals
Heart and Kidneys
All sympathetic target organs
except heart
Responses
-Stimulation of smooth muscle and
exocrine gland secretion.
-Decrease heart rate and contraction
-Skeletal Muscle contraction
-PNS and SNS stimulation
-Constriction of blood vessels
-Dilation of pupils
Inhibition of NEpi release
-Increased heart rate
-Increased force of contraction
-Release of renin
-inhibition of smooth muscle contraction
Drug Type
Target
Muscarinic/Cholinergic Parasympathetic
Agonists
targets
(Ach)
Heart
Muscarinic/Cholinergic Parasympathetic
Antagonists (Ach)
targets
Heart
Nicotinic Agonists
(Ach)
Nicotinic Antagonists
(Ach)
Released from
postganglionic
neurons to
stimulate
skeletal muscle
Ganglia and
adrenal medulla
Released from
postganglionic
neurons to
stimulate
skeletal muscle
Ganglia and
adrenal medulla
Therapeutic Use
-Increase the smooth muscle
tone and contraction of GI
tract
-Stimulate smooth muscle of
urinary
-stimulate most exocrine
glands
-Eye- causes sphincter
muscle of eye to contract
(constricting pupil)
-Causes contracting of the
ciliary muscle which causes
lens to flatten,
-GI-suppresses secretion
and motility
-Relaxes bladder
-pupil dilation (ophthalmic
use)
-CV- bradycardia
-Respiratory: dilates bronchi
(asthma)
-Poison antidotes
-Act by activating the Ach
receptors at ganglia
-Nicotine is the only drug
that is used therapeutically
-Smoking cessation
- Neuromuscular blockers –
not for chronic use
-Facilitate surgery
-Facilitate electroconvulsive
therapy
-Facilitate endotracheal
intubation
-Treat tetanus
Side Effects
-GI –
cramps/nausea/diarrhea/salivation
-Urinary urgency
-Vasodilation
-Sweating
-Contracts bronchial smooth
muscle
-Lower HR and BP à may cause
reflex tachycardia
-Tachycardia
-Dryness (mouth eyes)
-GI/Urinary Retention
-Dizziness and fatigue
-Toxicity – Anticholinergic
syndrome (dry mouth, blurred
vision, photophobia, difficulty
swallowing, hallucination)
-Acts at ganglia, therefore both
PNS and SNS effects
-Increased alertness
-Increased HR and BP
-Stimulated emetic center causing
nausea
-Large amounts = respiratory
paralysis
-Respiratory paralysis
-cardiac collapse
-Interaction alter neuromuscular
blocking
-Slow GI motility
Drug Type
Target
Alpha 1 – Agonists All sympathetic
Adrenergic
targets except
heart
Beta 1 – Agonists
Adrenergic
Beta 2 – Agonists
Adrenergic
Alpha 1 –
Antagonists
Adrenergic
Beta Antagonists/
Blockers
Heart and
Kidneys
All sympathetic
target organs
except heart
All sympathetic
targets except
heart
Heart and
Kidneys
Therapeutic Use
-Causes vasoconstriction (relieves
congestion, Increase BP, Local
anesthetic, topical hemostatic)
-Topical to eye (dilates pupil for eye
exams, relieves redness)
-Cardiac arrest
-Heart failure
-AV block
-Shock
-Relaxation of bronchiolar smooth
muscle (asthma/COPD)
-Relaxes uterine smooth muscle
(preterm labor contractions)
Side Effects
-Reflex congestion
-Increase BP
-Increase HR / BP
-Arrythmias
-Tachycardia
-Palpitations
Most important site of action is
lung
-Used locally to vasodilate to
prevent local necrosis
-Shock - vasodilation can pull fluid
back into circulation
-Pheochromocytoma
-Hypertension
-Orthostatic hypotension (first
dose phenomenon)/Dizziness
-Inability to ejaculate
-Cardiac arrhythmias
-Angina (decreases work of heart)
-Hypertension
-Controls signs of thyrotoxicosis
-Migraine prophylaxis
-Asthma/wheezing
-Fatigue/depression
-Nausea/Diarrhea
These drugs compete with NE
at the synapse, preventing
symptoms of fight/flight
Toxicity:
-Severe bronchoconstriction
-hypotension
-heart failure
Av block
-hypoglycemia in treated
diabetics
Contraindications: Asthma,
hypotension, heart failure,
heart block