Pharmacology of sympathetic nervous system

Question 1

activation of α1 -receptor

Answer 1

✦ smooth muscle contraction
✦ vasoconstriction
✦ mydriasis

Question 2

activation of α2 -receptor

Answer 2

✦ inhibition of neurotransmitter release (NA!)
✦ GI-relaxation
✦ inhibition of insulin release

Question 3

activation of β1 -receptor

Answer 3

✦ positive inotropic and chronotropic effects

Question 4

activation of β2 -receptor

Answer 4

✦ vasodilation
✦ bronchodilatation
✦ uterus relaxation

Question 5

activation of β3 -receptor

Answer 5

✦ lipolysis in fat tissue

Question 6

Pharmacological effect of sympathomimetic drugs. Cardiovascular system.

Answer 6

✦ positive chronotropic (β1)
✦ positive inotropic (β1)
✦ vasoconstriction (α1)
✦ vasodilatation (β2)

Question 7

Pharmacological effect of sympathomimetic drugs. Gastrointestinal system

Answer 7

✦ smooth muscle relaxation
✦ GI atony

Question 8

Pharmacological effect of sympathomimetic drugs. Respiratory system

Answer 8

✦ bronchodilatation
✦ decreased bronchial secretion

Question 9

Pharmacological effect of sympathomimetic drugs. Urinary bladder

Answer 9

✦ increased sphincter-constriction (α1)

Question 10

Pharmacological effect of sympathomimetic drugs. Eye

Answer 10

✦ mydriasis (iris radial muscles)
✦ increase in aqueous humor production

Question 11

list of non-selective sympathomimetics

Answer 11

✦ adrenaline
✦ noradrenaline
✦ dopamine

Question 12

Adrenaline (epinephrine). Indications

Answer 12

nonselective, mainy β1 and β2
arrhytmogenic!. Intratracheal/IV
Indications:
⋆ cardiac stop
⋆ severe bronchoconstriction
⋆ anaphylaxia
⋆ local vasoconstriction (haemorrhages)
⋆ increase in duration of local anaesthetics

Question 13

Noradrenaline (norepinephrine). Indications

Answer 13

⋆ nonselective (mainly β1 and α1), cardiac effect
⋆ blood pressure is significantly increased!
Indication (rare): hypotension

Question 14

Dopamine. Receptors?

Answer 14

low dose D1 - receptors (kidney!) → 2-5 µg/kg/min medium dose β1 - receptors (heart!) → 5-10 µg/kg/min high dose α1 - receptors (pressor) → 10-20 µg/kg/min

Question 15

β1-adrenoceptor agonists

Answer 15

Dobutamine (mainly β1)
Isoproterenol (β1 and β2)

Question 16

Dobutamine

Answer 16

mainly β1 receptors
indication: cardiogenic shock (IV. infusion)

Question 17

Isoproterenol

Answer 17

β1 and β2
heart+bronchi+muscle vessels

Question 18

Mainly β2 agonists:

Answer 18

bronchodilatation and uterus relaxation

higher dosage → β1 receptors → cardiac effect
⋆ clenbuterole
⋆ salbutamole
⋆ terbutaline
⋆ salmeterole
⋆ isoxsuprine

Question 19

Indications for β2 agonists:

Answer 19

⋆ horse RAO
⋆ feline asthma
⋆ bronchitis,
⋆ bronchopneumonia
⋆ tracheal hypoplasia
⋆ tracheal collapse

Question 20

Mainly α1 agonists

Answer 20

⋆ Phenylephrine (used rarely. vasoconstriction, usually local use: allergy, cold)

⋆ Xylometazoline, oxymetazoline (vasoconstriction, local usage)

⋆ Phenylpropanolamine (urinary bladder sphincter constriction!, PO usage)

⋆ Ephedrine (allergy, incontinence (p.o.))

Question 21

α2 agonists

Answer 21

xylazine, detomidine, medetomidine, romifidine

Question 22

Nonselective α-antagonists

Answer 22

Phenoxybenzamine (urethra sphincter relaxation)
Phentolamine
Tolazoline

Question 23

α1 antagonists

Answer 23

prazosine, doxasozine (urethra sphincter relaxation)

Question 24

α2 rec antagonists

Answer 24

atipamezole, yohimbine

Question 25

Nonselective β-rec antagonists

Answer 25

Propranolole

Timolole

Question 26

Selective β1 antagonists

Answer 26

Metoprolole
Atenolole

Question 27

What is the α1-agonist drug we MUST know?

Answer 27

Ephedrine