Re: why metoprolol is inverse agonist while propranalol is antagonist?

[Guest guest]

Hiii Tushar,

I would llike to answer your question. Actually I already replied

this one but It has not been yet aired, so I am repeating my post.

Selectivity of metoprolol for human cardiac â1- over â2-ARs ranges

from Thousands to hundred fold.Unoccupied â-ARs routinely at base

line i. e. inherently exert a basal amount of intrinsic activity,

translating into a basal level of adenylate cyclase activity and

cyclic adenosine monophosphate production. The ability of â blockers

to reduce this basal â-AR activity is termed " inverse agonist

activity. " ( You might have read my post on Inverse agonist)

Thus, when a â blocker does not simply " block " the receptor, but

further inactivates receptor activity beyond its baseline value, is

called inverse agonist.

But is some trials it is found that nonselective compound like

propranolol lacks this type of activity, for unknown reasons. Now it

is hypothesized that non selective compounds may be pure

antagonist….but again the things are not yet pretty clear.

Confusion increases when we go more in depth of this discussion and

remember the point that no agent has strictly pure activity on

single â-AR.

I don't know exactly the things about Famotidine, but it may be

related to its activity on histamine type 2 receptors.

As some one is asking a question to the point, I think he might not

be totally ingnorant about the facts. So I would like some more

inputs from you also.

Regards

Dr. Narendra

GMC, Nagpur

>

> what is inverse agonist.why famotidin and metoprolol r classified

as

> inverse agonist and propanalol not?

>

[Guest guest]

hi dear narendra

Thanks for giving attantion to my confusion.

after all surch i also know the thing u have sayed.all other are

even more confusing.and after this i asume that disease like HT also

have

a receptor level pathology due to mutation or etc and thats y inverse

agonist metoprolol has found most consistent of all.becoz it corrects

both receptor level and neurovascular level pathology.thanks again

for making effort to understand me this topic simply.

> >

> > what is inverse agonist.why famotidin and metoprolol r classified

> as

> > inverse agonist and propanalol not?

> >

>