Drugs affecting adrenergic synapses

In the adrenergic synapses the transmission is mediated by noradrenaline or

Noradrenaline (NE), dopamine and adrenaline are called catecholamines.
In presynaptic endings

The action of NE on receptors is short-term. It is mainly

The main α-adrenoreceptors include α1 and α2R.
Adrenoreceptors α1 have postsynaptic localization

Among β-R there are also post-, pre-, and extrasynaptic receptors.
Presynaptic

The main effects associated with the stimulation of post-and extrasynaptic adrenoreceptors
α1

α2 –adrenoceptor (extrasynaptic):
Vasoconstriction;
Increased platelet aggregation;
Decrease in insulin secretion.

β1 - receptors:

β2 - receptors:
Dilation of vessels of the skeletal muscles, liver, coronary;
Decrease

Classification
Drugs of presynaptic action, affecting release and storage of NE or

α and β adrenomimetics: Epinephrine, Norepinephrine;
α1: Phenylephrine;
α2: Naphazoline, Xylometazoline,

Epinephrine stimulates all types of AR.
It increases the force and

Mean arterial pressure increases.

E. relaxes smooth muscles of bronchi, eliminates bronchospasm. E. reduces the

E. stimulates
glycogenolysis (hyperglycemia occurs, blood concentration of lactic acid and

Local effects:
E. dilates the pupils (mydriasis) due to the contraction of

Duration of action: intravenously - 5-10 min., subcutaneous injections - up

Side effects: headache, fear, anxiety, tremor, vomiting, tachycardia, extrasystoles.

Norepinephrine stimulates predominantly α-adrenergic receptors and to a small extent β-AR.

Norepinephrine can not be administered subcutaneously due to the possibility of

Phenylephrine stimulates α1-AR but acts weaker than norepinephrine.
It increases arterial pressure

Indications for the use:
relief and prevention of shock and collapse,

Naphazoline, Oxymetazoline and Xylometazoline constrict the vessels of the nasal mucosa,

Isoprenaline stimulates all types of β-AR.
It stimulates β1-AR of the

The drug facilitates atrioventricular conduction and increases heart automatism.

I. decreases the tone of bronchi, muscles of gastrointestinal tract; causes

Salbutamol, fenoterol, salmeterol stimulate B2-AR. They expand the bronchi and are

Dobutamine stimulates β1-AR.
It moderately increases heart rate, stroke and minute

Violates the reverse neuronal uptake of NE; Inhibits MAO; Facilitates

Effects: It stimulates heart function, increases blood pressure, causes a broncholytic

Side effects:
tachyphylaxis with frequent use (reduction in norepinephrine storage in