Long Question:?

Isoprenaline (10mg/kg) administration contained by a normal anaesthetised animal increased heart rate from 100-175 bpm and halt systolic bp from 110-75mmhg. What drugs would you administer to define the mechanism causing these responses?Long Question:?
I'm not sure if I completely know the question. Are you motto, how can we prove that isoprenaline works on beta-1 receptors?
If so, then we could administer beta-antagonists close to propanolol and atenolol; if they antagonise (reverse/reduce) the effects of the isoprenaline (ie lower heart rate) then we enjoy proved that isoprenaline works on beta-1 receptors.
Or, we could do things like administer isoprenaline and PDE (phosphodiesterase) simultaneously, and show that when cAMP is broken down by the PDE, isoprenaline does not work, thus proving that isoprenaline's moving parts for increasing heart rate is to raise intracellular cAMP level. (It does this as cAMP opens Na+ channel, which initiates muscle contraction [thus increasing contractility and blood pressure, the latter by increasing smooth muscle contraction around the vasculature], and also decreases the 'If' current time, the one which is used surrounded by the SA node to determine the rate of depolarisation of the atria and ventricles, and therefore decrease heart rate).
We couldn't use parasympathomimetics to see what effect the isoprenaline was have, as these are physiological antagonists, not receptor antagonists - so these would have duplicate effect as, for example giving PDE, but by a different mode of action.

Well, I hope this is of some facilitate.
Ashley
Concise answer 1. a short acting beta blocker like Esmolol and 2. an alpha blocker similar to Phentolamine.