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21 terms

antagonist

a drug that neutralizes or counteracts the effects of another drug

mutually exclusive

In competive antagonism, the binding or agonist and antagonist are...

reversible competitive antagonism

This type of antagonist can be reversed with an increase in concentration of agonist

atropine (mAChR blocker

example of an reversible competitive antagonist...

irreversible competitive antagonism

This type of antagonist cannot be reversed without a complete regeneration of the system. Binds at same site as aognist

phenoxybenzamine (a blocker)

example of irrevesible competitive antagonist...

[A]'/[A]

concentration ratio=

-log [B]r=2

The negative logarithm of [A] which causes a CR of 2 is equal to...

gaddum equation

Expresses how the proportion of agonist bound receptors is dependant on the concentration of A and B.

pAR=[A]/kA(1+[B]/kB)+[A]

The gaddum equation

CR

r=

r-1=[B]/kB

The schild equation

Schild equation

Equation demonstrating parallel shift in concentration response curves and estimation of kB

intercept of X plot axis

pkB is equal to the...

log(r-1) = log[B] - log(kB)

Schild equation in logarithmic form

classification of receptors and agonists, assessment of new antagonists

Practical applications of competitive antagonism study...

kB value

Each receptor has a unique..

CR is the same as a well characterised A

It is possible to test if a new agonist acts at a given receptor by examining whether the...

reversible non competitive antagonism

Insurmountable antagonist which binds at site other than that of agonist

hexamethonium

example of RNCA that blocks nicotinic ion channels

open channel block

RNCA can only bind when ion channel is open