Background
Methods
Adrenergic receptors (Table 1)
α-receptor | β-receptor | Dopamine-receptor | |
---|---|---|---|
Subgroups | α1, α2
| β1, β2, β3
| D1, D2, D3, D4, D5
|
Mechanism of action | G-protein coupled receptors | G-protein coupled receptors | G-protein coupled receptors |
Molecular effects | α1: Activation of PLC, IP3 mediated intracellular calcium increase α2: Decreased cAMP production | Increase of cAMP, protein phosphorylation (β1, β2, β3), intracellular calcium increase (β1) or decrease (β2) | D1, D5: Increase of cAMP D2, D3, D4: Decreased cAMP production |
Hemodynamic effect | α1: Vasoconstriction↑ α2: Mixed (vasoconstriction or vasodilation) | β1: Heart rate↑, contractility↑ β2: Vasodilation↑ | D1, D5: Vasodilation↑ D2, D3, D4:: Vasoconstriction↓ |
Dominant location | α1: Smooth muscle α2: Central nervous system | β1: Cardiac tissue β2: Smooth muscle β3: Adipose tissue | D1, D2, D3, D4, D5:
Central nervous system |
β1-receptor function during hypothermia
Adrenergic receptor agonists (Table 2, Fig. 1)
Adrenaline
Adrenaline | Noradrenaline | Isoprenaline | Dobutamine | Dopamine | |
---|---|---|---|---|---|
Species | Rat, dog | Cat, dog, | Rat, dog, rabbit, guinea pig | Dog, pig, rabbit, guinea pig | Dog, pig |
Dosage (in vivo) | 0.4 μg/kg/min – 4.2 μg/kg/min | 0.2 μg/kg/min – 5.0 μg/kg/min | 5.7 ng/kg/min – 1 μg/kg (bolus) | 2.0 μg/kg/min – 30 μg/kg/min | 2.0 μg/kg/min – 30 μg/kg/min |
Administration | i.v. (in vivo studies), Retrograd coronary perfusion (in vitro studies) | i.v. (in vivo studies) | i.v. (in vivo studies), Retrograd coronary perfusion or in preparation solution (in vitro studies) | i.v. (in vivo studies), Retrograd coronary perfusion or in preparation solution (in vitro studies) | i.v. (in vivo studies) |
Target temperature | 12 °C–28 °C | 28 °C–30 °C | 20 °C–28 °C | 22 °C–31 °C | 25 °C–30 °C |
Cardiac effect (hypothermia) | Reduced or depressed inotropic effect (in vitro) [56]. |