THE EFFECT OF MIXED BOVINE BRAIN GANGLIOSIDES ON HYPOXIC CONDUCTION BLOCK IN CONTROL AND STREPTOZOTOCIN-DIABETIC RATS

This study describes the electrophysiological responses of endoneurial preparations derived from rat sciatic nerve to acute hypoxia in vitro. Preparations from control rats exhibited a 40% decline in compound action potential (CAP) amplitude after 40 min exposure to medium gassed with 8% O2. In preparations from 4 week streptozotocin-diabetic rats CAP declined by only 29%, indicating a resistance to hypoxic conduction blockade. Treating diabetic rats with mixed bovine brain gangliosides (10 mg/kg/day i.p.) exaggerated this resistance to hypoxic conduction blockade as CAP amplitude fell to only 18% of initial values. In a separate experiment, treating non-diabetic rats with gangliosides (10 mg/kg/day i.p.) or adding gangliosides (400-mu-g/ml) directly to the medium in which control nerves were maintained during in vitro recording also significantly attenuated the decline in CAP amplitude after 40 min hypoxia, thus effectively inducing a resistance to hypoxic conduction blockade similar to that observed in nerves from diabetic rats. These studies demonstrate that the systemic or acute local administration of gangliosides induces a resistance to hypoxic conduction block in normal nerve and exaggerates the resistance to hypoxic conduction block od diabetic rats.