Posted by undopaminergic on June 30, 2008, at 13:22:44
In reply to Re: beta2- and beta3-adrenoceptors, posted by dbc on June 26, 2008, at 14:25:56
> I imagine this would have a major effect on things like blood pressure and might be a bit risky.
>Beta2-adrenoceptors dilate blood vessels, thus lowering pressure, but they also increase heart rate, which raises blood pressure. The net effect may be either lowered or increased blood pressure, depending on dose and other factors.
Treatment with beta2-agonists after a heart attack (myocardial infarction) is generally more beneficial than the standard protocol, which is treatment with beta1-antagonists ("beta-blockers"). One of the reasons for that is that beta2-agonists dilate coronary blood vessels, thus enhancing myocardial perfusion and oxygenation.
It's my conclusion that beta2-adrenergic stimulation is pretty safe from a cardiovascular point of view, except perhaps under certain pathological conditions.
Beta3-adrenoceptors seem to be even more effective (than beta2-ones) in enhancing the uptake of aromatic amino acids across the blood-brain-barrier and into the CNS. They also stimulate lipolysis, and may therefore be useful in getting rid of surplus fatty tissue. To my current knowledge, beta3-adrenoceptors are of little or no cardiovascular significance (although I suspect a more thorough investigation would reveal some minor involvement).
poster:undopaminergic
thread:836314
URL: http://www.dr-bob.org/babble/neuro/20080418/msgs/837316.html