Immunopharmacological studies on Picrorhiza kurroa Royle-ex-Benth. Part III: Adrenergic mechanisms of anti-inflammatory action.

Nature of adrenergic mechanisms contributing to anti-inflammatory effect of Picrorhiza kurroa suggested from earlier studies was explored in Wistar albino rats. Water soluble fraction of alcoholic extract of rhizomes (PK) potentiated castor oil-catharsis on oral administration but direct subplanter PK-injections failed to exhibit any local irritancy and oedema. Propranolol pretreatment counteracted while phentolamine enhanced anti-inflammatory effect of PK in carrageenin-induced inflammation. 6-hydroxy-dopamine pretreatment antagonised the said PK-effect and in such animals both ephedrine and isoprenaline augmented anti-inflammatory effect of PK, the former interaction being more conspicuous. PK-treatment of rats did not influence adrenaline uptake by lung slices in vitro. The results suggest that a non-neural augmentation of beta-adrenoceptor function or consequent cellular events mediates the anti-inflammatory effect of PK.