and kappa agonists were tested to see if they stop acute mania and they do.
kappa agonists also block cocaine reward
opioids influence mood rapidly and robustly and without strange sideeffects of dopaminergics of sertonoergics.
they are mainly responsible for mood and in them lies the answer to most issues. it is really sad it takes them so long to figure this out.
what else did they think would influence mood other than the reward fear system? seeing possibilities of rewards makes you elated and even fearless. seeing possibilities of stress makes you anxious and also anhedonic. this is simple as 1-2-3.
mu opioids always cause better mood.
kappa opioids always cause worse mood.
no other neurotrasmitter is THAT precise in mood control in the sense that it doesn't cause any other weird effects.
dopaminergics can increase reward perception as much as anxiety perception. it's just a "drive/perception/focus control" network. pushing it causes all kinds of sideeffects.
serotonergics are even more weird, they seem like a "purge" neurostramitter type network(purge bowels, purge/integrate memories to subconscious? not sure). and cause even more sideeffects
noradrenergics make you nervous, stimulate the HPA, make you angry etc..
point is, they're messing with "drive", dopamine and/or noradrenaline , not the source or "direction" of the drive.
increasing dopamine increases perception of fear and desire alike. as does oxytocin increase distrust as much as trust. obviously there's another network(although it might also be a part of opioid network) that facilitates is someone trusted or not. oxytocin only multiplies/amplifies this "value". dopamine does this for fear/desire - multiplies/amplifies it.
Edited by addx, 12 August 2013 - 09:12 AM.