I'm a bit confused with epinephrines mechanism of action in low doses.
It acts on alpha 1 receptors in the venous system, increasing venous return. I'm not entirely sure this is the right mechanism (correct me if I'm wrong) but by increasing venous return, it increases preload, which increases SV and thus increasing the amount of blood in the arterial system, increasing diastolic pressure. However in low doses, it acts more on b2 receptors, dilating skeletal arterioles and this outweighs the a1 venoconstriction, to overall decrease diastolic BP. (is this correct?)
Meanwhile it also acts on a1 receptors in systemic arterioles, increasing systolic pressure.
I might have this completely backwards. But I'm having difficulty tying in all the receptor effects to their corresponding changes in diastolic/systolic BPs.
It acts on alpha 1 receptors in the venous system, increasing venous return. I'm not entirely sure this is the right mechanism (correct me if I'm wrong) but by increasing venous return, it increases preload, which increases SV and thus increasing the amount of blood in the arterial system, increasing diastolic pressure. However in low doses, it acts more on b2 receptors, dilating skeletal arterioles and this outweighs the a1 venoconstriction, to overall decrease diastolic BP. (is this correct?)
Meanwhile it also acts on a1 receptors in systemic arterioles, increasing systolic pressure.
I might have this completely backwards. But I'm having difficulty tying in all the receptor effects to their corresponding changes in diastolic/systolic BPs.