Electrotonic coupling between neurosecretory cells in the crayfish eyestalk

Abstract

Electrical coupling is described among neurosecretory cells in the crayfish X organ. By simultaneous impalements from pairs of neurons, only 30% were found to be coupled. All of them showed non-rectifying junctions. In all cases, electrical coupling corresponded to dye-coupling, as explored with intracellular injection of Lucifer yellow to one of the recorded cells. Some neurons were coupled to more than one neighbour. From dye fills it was apparent that the coupling site could be located far away from the cell body, immediately before the axonal branchings in the neuropile. The input resistance of the coupled neurons was consistently lower (24 +/- 16 M omega) than that of the non-coupled neurons (58 +/- 18 M omega). Synchronous synaptic activity was commonly recorded from coupled neurons, thus suggesting a functional significance of coupling in the integration of neurosecretory activity.