RESPONSIVENESS TO D-GLUCOSE IN NEUROSECRETORY-CELLS OF CRUSTACEANS

1. An electrophysiological study of the D-glucose sensitivity of X-org an (XO) neurosecretory cell bodies in crayfish was carried out with th e use of microelectrodes, perforated, and cell-attached patch-clamp te chniques. 2. Glucose depolarizes the membrane potential of XO cells in a concentration-dependent manner. 3. Depolarization produced by gluco se initiates a change in the pattern of electrical activity. Silent ce lls began to discharge action potentials. When bursting cells are depo larized by glucose, their action potentials are no longer grouped in b ursts or disappear entirely. 4. Although the membrane potential return s to its initial value after removing glucose from the bath, discharge patterns of the cells may remain different. This suggests that beside s the depolarizing effect, once the cells have been exposed to glucose , the sugar switches on a process that is maintained for a long time. 5. Glucose produced a reduction of membrane steady-state conductance, and a shift of reversal potential of membrane currents to a more posit ive value. 6. Depolarization induced by D-glucose appears to be relate d with a closure of potassium channels. 7. Glucose effect was thought to be generated by a product of metabolism that would act as intracell ular mediator.