Post on 29-Jan-2018
Effects of
sympathomimetics outside
cardiovascular system
Domina Petric, MD
Activation of β2-receptors in smooth
musculature of bronchi
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Results inbronchodilatation.
That is why are β2-agonists veryimportant in asthmatreatment.
Healthy Liverpool
In the eye muscle dilator pupillae has α-
adrenergic receptors: effect is mydriasis.
Alfa-receptors stimulators decrease
production and increase drain of occular water
from anterior eye chamber which causes
decrease in the intraocular pressure.
“Base of urinary bladder, sphincter urethrae and
prostate have α1-receptors that cause these
structures to contract and hold urine. Midodrine
(α1-receptor agonist) can cause urine retention.
α-receptors are very important for normal
ejaculation and for cessation of erection after
ejaculation.
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Salivary glands
∙ Salivary glands have adrenoreceptors that
regulate secretion of amilase and water.
∙ Klonidin is an example of sympathomimetic
that causes dry mouth.
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Sweat glands
Adrenalin causes increased
sweating. Activity of
apocrine sweat glands on
the palms is associated
with psychological stress
and those glands do not
participate in regulation of
body temperature.
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Activation of β-receptors in fat tissue
increases lipolysis and release of free fatty
acids and glycerol in the blood. Fat cells also
contain α2-receptors that inhibit lipolysis (by
lowering intracellular cAMP).
Sympatomimetics increase glycogenolysis in
the liver with increased release of glucose in
the circulation.
Metabolic processes
High concentration of catecholamines can
cause metabolic acidosis.
Activation of β2-receptors with endogenous
adrenalin induce potassium ions intracellular
uptake wich causes decrease of potassium
levels in the circulation. This mechanism is a
protection from hyperkalemia during
physical stress and excercise.
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Metabolic processes
∙Activation of beta-receptors in
pancreatic islets causes mild
increase in insulin secretion, whilst
activation of α2-receptors
decreases insulin secretion.
∙Plasma glucose level is the most
important insulin secretion
regulator.
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Other hormones secretion
Activation of β1-
receptors stimulates
renin secretion, whilst
activation of α2-
receptors inhibits
renin secretion.
Adrenergic receptors
modulate parathyroid
hormon, calcitonine,
thyroxine and gastrin
secretion with
moderate significance.
In high
concentration
adrenalin causes
leukocytosis.
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Central nervous system
∙Catecholamines do not pass blood-brain barrier and do
not cause central effects, except in the case of high
speed infusion.
∙Amphetamine passes through blood-brain barrier and
has stimulative effect on the central nervous system.
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