Depolarizing neuromuscular junctional blocking action of Parthenium hysterophorus leaf extracts in rat

Electromyographic (EMG) and electrodiagnostic studies were made on sciatic nerve-anterior tibialis muscle in vivo in rats administered with a subletha l dose of Parthenium hysterophorus dry leaf powder 100 mg/100 g body weight of rat. Nerve-evoked and muscle-evoked compound muscle action potentials w ere recorded at different frequencies of stimulations and at different time intervals. The EMG studies revealed depolarizing neuromuscular junctional (NMJ) blocking effects of the leaf extract. The decrement-increment (D-I) p henomena and the EMG pattern in general showed a resemblance to an establis hed anticholinesterase agent like neostigmine, The studies confirm that the leaf extract contains a proven and promising new depolarizing NMJ blocker. Copyright (C) 1999 John Wiley & Sons, Ltd.