Changes in the extracellular space of Callinectes sapidus axons during osmotic shocks

Abstract

1. 1. Estimations of the extracellular space (ECS) of isolated axons of sea-water-acclimated Callinectes sapidus give a mean value of 29·5 per cent (ml/100 g tissue wet wt.). 2. 2. There is no significant difference between the ECS of axons of crabs acclimated to sea water or to twice-diluted sea water. However, when axons of sea-water crabs are submitted to a hyposmotic stress, the ECS is transitorily decreased but resumes its control values in less than 2 hr. During the hyperosmotic stress, an increase in the relative volume of the ECS can be observed. 3. 3. These results are discussed in relation with the changes in axonal volume occurring during osmotic shocks.