Posted by undopaminergic on April 4, 2008, at 4:16:47
In reply to Re: High BP on Selegiline! B-Blockers, good?, posted by Amigan on April 4, 2008, at 0:39:51
> > >
> > > > Probably a beta blocker would be the best drug to try to prevent the increase in blood pressure due to norepinephrine.
> > >
> > > how sure are you about this? From what i have read, beta blockers can have exactly the opposite results in the present of a sympathomimetic factor and perhaps in cases of excessive NE, too.
> > > The Beta receptors in blood vessels are responsible for vasodilation, while the Alpha receptors for vasoconstriction. THUS, if you block the B receptors, while the Alpha ones remain stimulated by the excessive N,NE or the SM factor, you have an increase in blood pressure.
> > >
> >
> > Beta2-adrenoceptors mediate many of the (usually) desirable effects of adrenaline - including vasodilation, bronchodilation, and reduction of allergic responses, although they also increase heart rate, and their improvement of muscular blood flow may have undesirable side-effects (e.g. tremor). Selective beta1-adrenergic antagonists ("cardioselective" beta-blockers) should leave the beta2-receptors alone, but their primary effect is to reduce heart rate, which will reduce blood pressure, but not reverse the effects of vasoconstriction caused by selegiline-induced noradrenaline release (assuming that is the cause of your elevated BP).
>
> No. We are not talking about adrenoreceptors. I'm talking about ordinary, post-synaptic antagonism of the B adrenergic receptor (the standard pharmacological action of all B-Blockers)
>Then you are talking about adrenoceptors - more precisely, you're talking about the blockade of post-synaptic beta-adrenoceptors (or beta-adrenergic receptors, if you prefer, but that's the same thing).
Anything else about what I wrote that needs further clarification?
poster:undopaminergic
thread:819397
URL: http://www.dr-bob.org/babble/20080330/msgs/821499.html