Effects of dielsin b on nerve-muscle preparations

Expcriments were carried out on rat phrenic nerve-diaphragm preparations and chick biventer cervicis nerve-muscle preparations. Dielsin B l. 5 Vg/ml blocked the neuromuscular transmission without affecting the conductivity of nerve and muscle contractile response to direct stimulus. It altered the quantal content of the end-plate potential and the frequency of miniatur end-plate potential. but did not affect the resting potential and the acetylcholine sensitivity of muscle. Washing did not restore the neuromuscular transmission blocked by dielsin B, but high Ca++ did so effectively. The effects of dielsin B were compared with those of yunaconitine on the neuromuscular transmission.