Usually, for animal model development we first induce disease in animal and then, we give the test compound to cure the induced disease and observe the effect.
But in some texts I have read they give test drug before disease induction
For. e.g -: Digoxin induced Arrhythmia in Guinea pigs
After anesthetization of Guinea pig then digoxin is infused through jugular vein, but in the text it is written that the test drug is given i.v. prior to infusion.
Why is the test drug is not given directly after digoxin infusion, and why before?