Posted by undopaminergic on June 30, 2008, at 15:09:05
In reply to Alpha blockers effect on mood?, posted by Jimmyboy on June 29, 2008, at 22:40:32
Blocking the alpha2A-adrenoceptor results in increased release of noradrenaline (NA). Slight increases in synaptic NA may improve alertness, attention, and possibly mood. Excessive synaptic NA levels may impair working memory and produce nervousness, agitation, restlessness, and so on. Additionally, excessive NA may produce sweating, rapid heartbeat and hypertension, but may be beneficial for male sexual function. Blockade of postsynaptic alpha2A-adrenoceptors disrupts working memory and executive functions. Examples of drugs exerting alpha2A-antagonist actions are yohimbine and mirtazapine.
Blockade of alpha2B- or alpha2C-adrenoceptors is likely to produce certain cognitive deficits, such as impaired executive functions, but probably of a more subtle nature than alpha2A-blockade.
Alpha1-adrenergic antagonists lower blood pressure, but not heart rate. They may reduce sweating and cause nasal congestion, flushing, and some other symptoms. The effects of central alpha1-adrenergic antagonism are not as well characterised as the peripheral effects. However, it's likely that excessive blockade of alpha1A-adrenoceptors would impair working memory, and perhaps attention. Blockade of alpha1B-adrenoceptors would probably be more detrimental, possibly producing lethargy, impaired concentration and alertness, or even apathy.
I'm pretty sure there's one more subtype of alpha1-adrenoceptors, but I have nothing to say about it at this time.
The above is my current recollection from memory, and has not been verified, so some of it may be inaccurate. It is certainly incomplete.
poster:undopaminergic
thread:837233
URL: http://www.dr-bob.org/babble/neuro/20080418/msgs/837345.html