The drugs guanfacine and clonidine are agonists (they increase the activity) of adrenaline alpha 2 receptors, and yet this drug lowers the level of adrenaline in the brain and in the body, and lowers blood pressure. How is such a paradox possible?
The catch lies in a very gross error – even in cutting-edge science, mistakes are made: adrenaline alpha 2 receptors were mistakenly named "adrenaline" receptors, but the name has stuck. They should not be called "adrenaline" receptors – it's a mistake. The correct naming of receptors is based on the neurotransmitter substance to which the receptors are bound. The neurotransmitter substance of adrenaline alpha 2 receptors is not adrenaline. Therefore, when the activity of these receptors increases, blood pressure drops and adrenaline production in the brain decreases.