EFFECT OF ALLOSTERIC SNAKE NEUROTOXIN ON NEUROMUSCULAR JUNCTION / 第二军医大学学报

ABSTRACT

The present study reports direct effects of allosteric snake neurotoxin (MN-81) on the nicotinic acetylcholine receptor (N-AChR) and on the transmission of nuro-muscular junction. when one dose of MN-81 with 50 ?g/kg body weight was injected into the mice, the number of N-AChR binding sites was not changed. when one dose of MN-81 with 250 ng/kg body weight was injected, 23 per cent of total N-AChR were occupied by MN-81 molecules. But when repeated injection of MN-81 was carried out N-AChR binding sites were increased by about 34 percent. Assay of phrenic nerve-diaphragm showed that the low close of MN-81 increased contractile amplitude of isolated rat diaphragm and rabbit diaphragm in situ, while an increase in the concentration of MN-81 (10-4g/ml) led to blockade of nuromus-cular transmission.