Alpha 1 vs 2 agonists

Hi

I have a question in regards to the mode of action of Alpha 1 agonists vs Alpha 2 agonists. It seems as though Alpha 1 agonists are generally associated with vasoconstriction where as alpha 2 agonists are identified as vasodilators such as clonidine. Trying to understand the mechanism behind this considering that alpha 1 antagonists are also identified as anti-hypertensives. Very confusing!!

Thanks in advance

Make sure you know the difference between an agonist and antagonist when defining medications and you will have answered your own question.

Best of luck.

Alpha2-receptors actually causes a negative feedback on norepinephrine (a sympathetic nervous system neurotransmitter), so by stimulating alpha 2 (agonist such as clonidine) you actually inhibits SNS and that leads to the opposite of sympathetic responses.

Alpha2-receptors also lower insulin release which is why clonidine can cause a spike in blood glucose.