Measurement of drug action at receptors

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What is radioligand binding?
labelling a drug with a radioactive isotope to detect and measure the amount of drug bound in tissue samples.
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Steps for radioligand binding
1. Homogenise brain and divide equally in two sets. 2.First set incubate tubes with varying levels of labelled drug. 3.Second set incubate with labelled and lots of non-labelled cold drug.
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Continued.
filter and wash samples so only bound to tissue left. measure amount of radioactivity. First set is total binding, second set in non-specific as all receptors taken by cold resin. 2-1 to get specific called a saturation plot. can work out kd and bmax
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What is Bmax and Kd?
Bmax-maximum number of receptors per tissue. Kd-affinitiy of radiolabelled drug (conc of drug to occupy 50% receptors)
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What is PA2?
Negative logarithum of conc of antagonist that necessitates that you double the agonist conc to produce the same response (dose ratio-2)
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What is the Schild equation?
log(dose ratio-1)=log(con antagonist)-logKb (kb- antagonist dissociation equilibrium constant)
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What is Dose ratio?
The extent to which the curve shifts shows the affinity of the antagonist. shift measure of response produced with and without antagonist.
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Other cards in this set

Card 2

Front

Steps for radioligand binding

Back

1. Homogenise brain and divide equally in two sets. 2.First set incubate tubes with varying levels of labelled drug. 3.Second set incubate with labelled and lots of non-labelled cold drug.

Card 3

Front

Continued.

Back

Preview of the front of card 3

Card 4

Front

What is Bmax and Kd?

Back

Preview of the front of card 4

Card 5

Front

What is PA2?

Back

Preview of the front of card 5
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