Exogenous gangliosides induce direct voltage and conductance changes on isolated neurons.

1. The effects of pressure-ejected ganglioside GM on the electrical characteristics of neurons in the abdominal ganglion, which themselves are devoid of endogenous gangliosides, were studied using voltage-clamp recording techniques. 2. Some but not all neurons were found to respond to ganglioside application at 10 with either depolarizing or, more rarely, hyperpolarizing responses. About half of the RB (an identified cluster of neurons in the abdominal ganglion) neurons studied showed the depolarizing response, which was also obtained in cell R. LB (another identified cluster) neurons showed the hyperpolarizing response. 3. The depolarizing responses were associated with a conductance increase to Na, while the hyperpolarizing responses were associated with a conductance increase to Cl. 4. The response to ganglioside application showed a reversible decrement on repeated application, suggesting a receptor desensitization. There was no cross desensitization with responses to acetylcholine. 5. While the functional significance of these responses, if any, is unknown, these actions of gangliosides may be important in understanding both the physiologic functions of this class of compounds and their neuritogenic growth effect.