Gap-like junctions between neuron cell bodies and glial cells of crayfish.

Data reported up to now on neuron-glia relationships, show that neuron cell bodies and glial cells are separated by a narrow intercellular cleft which is considered as the microenvironment of the nervous system, and where neuron-glia exchange occurs. We present here evidence that neuron perikarya and ensheathing glial cells of the abdominal ganglia of the crayfish communicate through gap-like junctions. These junctions could constitute short circuits for ionic exchange between neuron perikarya and glial cells, probably with some degree of electrotonic coupling between neurons and glia. In the preparation described here, the intercellular cleft would play only a secondary role in neuron-glia communication.