Potencies for different receptors
These 4 graphics show the potencies of 3 agonists (adrenaline, noradrenaline, isoprenaline) for the different adrenergic receptors.
The potency of the 3 agonists for the α1 and α2 receptors is similar:
- Adrenaline and noradrenaline are equally potent for both receptors
- Isoprenaline is less potent for both receptors.
The 3 agonists display different potency patterns for β1 and β2 receptors:
- Isoprenaline is the most potent for both β1 and β2.
- For the β1 receptor adrenaline and noradrenaline are both less potent than isoprenaline, but with about the same ED50.
- For the β2 receptor, noradrenaline is the least potent of all 3 agonists and adrenaline has intermediate potency.