α2 (Alpha-2 adrenergic)

[Abject]

What roles does α2 play?
I was on Mirtazapine a while ago, and it was making me quite lethargic. In that state of mind I decided to take .2-3mg iirc mirtazapine in an attempt to desensitise my receptors with the hopes of lessening the lethargy (my poor brain)
Looking at the localisation α2 has in the body, I'm just wondering what sort of role it has.
It was some time ago, and I don't (nor have I) felt any different, so I'm not too worried I did any major damage, I'm more interested in see just how stupid it is to fuck around with an α2 antagonist (maybe in comparison to α1?)
I see that Catecholamines signal through it, but what affects do NA and epinephrine have constantly, rather than triggered release.

 

[sekio]

It's a whole class of adrenergic receptors. Among other things a2 receptors are responsible for maintaining blood pressure through vasoconstriction, modulating levels of (nor)epinephrine through negative feedback, and maintaining arousal and wakefulness.

Yohimbine and the kratom alkaloids exert their stimulant effects by a2a antagonism (blocking the a2a autoreceptor makes the body think its levels of NE have dropped, so it releases more). Mirtazepine is in this group, but it also has a lot of other effects. In general people report it as being... non-euphoric.