Exploration of Mechanism of Action of Ephedrine on Rat Blood Pressure
The aim of the study is to study mechanism of action (direct, indirect or mixed) of ephedrine on rat blood pressure by using agents affecting synthesis, storage and release of noradrenaline. 30 male Wistar albino rats divided into 6 groups (n=5). A: ephedrine control, B: tyramine control, C: reserpine + metyrosine + ephedrine, D: reserpine + metyrosine + tyramine, E: desipramine + ephedrine, F: desipramine + tyramine. In A and B: blood pressure responses of ephedrine and tyramine were taken for control, C and D: reserpine was injected 18 hrs. before and metyrosine was injected 2 hrs before taking responses of ephedrine or tyramine respectively. For E and F: desipramine was given 10 min. before taking response of ephedrine or tyramine respectively. Rat mean blood pressure was measured by using student’s physiograph. Reserpine and metyrosine, inhibits the vesicular uptake and synthesis of noradrenaline respectively decrease the pressor responses of tyramine significantly (p=0.000) but not of ephedrine (p=0.893).Prior administration of desipramine which inhibits axonal uptake of noradrenaline also significantly decreases the effect of tyramine (p=0.000) but do not affect the effect of ephedrine significantly (p=0.893).Study concludes the pressor effect of ephedrine is not mediated by release of noradrenaline from neurons, indicating that ephedrine act directly on adrenergic receptors.
Paresh Solanki, Preeti Praveen Yadav, Naresh D Kantharia