What is the mechanism for the antihypertensive actions of Clonidine?
Clonidine is an alpha2-receptor agonist. Alpha2-receptors can be found both pre- and post-synaptic. It is thought that the alpha2 agonists like clonidine exert their antihypertensive action via post-junctional receptors in the CNS. Stimulation of these receptors inhibits the activity of the vasomotor center with subsequent decrease in sympathetic outflow from the CNS . It is not that important that they are either pre- or post-synaptic receptors, but the antihypertensive action of alpha2-agonists is due a CNS -mediated action to decrease sympathetic outflow. Clonidine can stimulate presynaptic alpha2-receptors on the nerve terminal to decrease NE release but this is not the cause of its use as an antihypertensive agent.
