Isoproterenol (or isoprenaline) is a non-selective beta-adrenergic receptor agonist, that is particularly potent on beta1- and beta2-receptors and at higher doses also at beta3 receptors.

Isoprenaline is a synthetic sympathomimetic compound related to adrenaline that non selectively stimulates beta receptors with very little effect on alpha receptors. Stimulation of Beta 1 receptors increases heart rate , myocardial contractility , cardiac output as well as myocardial oxygen consumption. 

On the other side stimulation of Beta 2 receptors results in dilatation of skeletal ,vessels resulting in a drop in vascular resistance with little or no effect on systolic blood pressure but MABP usually falls  . 

The increased myocardial work and increased oxygen consumption in a patient with CAD increases the risk of critical ischemia and myocardial necrosis and thus it should be used cautiously in these people.

The drug relaxes bronchial and gastrointestinal smooth muscles producing a bronchodilator effect.

increased cardiac output and increased strenth of cardiac contraction , decreased peripheral vascular resistance(afterload) increased blood return to heart (preload) stimulation of beta receptor ,fascilitates removal of pulmonary secretions increasing cilliary motion

Dear Colleague, the attached 3 papers, being related to your Q, might be interesting to you, hopefully...

George

Hi Shobana,

a single injection of isoproterenol causes diffuse myocyte death through calcium leakage secondary to an acute dysfunction of ryanodine receptor.

You might be interested in checking this paper out.

http://www.ncbi.nlm.nih.gov/pubmed/17237229