SYMPATHETIC NERVOUS SYSTEM
β 2 (Gs-coupled)
PARASYMPATHETIC NERVOUS SYSTEM
The dominant effect of SNS is mediated by α1 and β1 receptors. α2 and β2 action will become dominant when any drug will block α1 and β1 receptors.
α1 decreases renin release while β1 increases renin release. There are many other systemic effects of these receptors. Don’t forget about them while combining medications.