1. An electrophysiological method was used to estimate the half-times for sodium and potassium entry to, and efflux from, the extra-axonal space in peripheral nerve and central nervous connectives of two species of crustacean. Results from crab (marine) and crayfish (fresh water) were qualitatively similar. 2. Peripheral nerve showed no evidence for diffusion barriers, potassium entry and efflux being rapid, and proceeding at comparable rates. 3. In connective, potassium entry was extremely slow, with a half-time greater than 100 min, while potassium efflux was relatively rapid (T 1/2 = 6 min). Sodium movements were less restricted, but sodium entry was more rapid than sodium efflux. 4. The potassium experiments were compared with the behaviour of a theoretical model system. Evidence is presented for diffusional restriction to potassium at the connective perineurial layer. The mechanism of restriction may involve changes in permeability or activation of an ion pump in the perineurial layer. 5. The physiological significance of these findings is discussed.
In the field: an interview with Martha Muñoz
Martha Muñoz is an Assistant Professor at Yale University, investigating the evolutionary biology of anole lizards and lungless salamanders. In our new Conversation, she talks about her fieldwork in Indonesia, Costa Rica, the Dominican Republic and the Appalachian Mountains, including a death-defying dash to the top of a mountain through an approaching hurricane.
Call for new preLighters
(update)-CallForPreLighters.png?versionId=3981)
preLights is the preprint highlighting community supported by The Company of Biologists. At the heart of preLights are our preLighters: early-career researchers who select and write about interesting new preprints for the research community. We are currently looking for new preLighters to join our team. Find out more and apply here.
Graham Scott in conversation with Big Biology
Graham Scott talks to Big Biology about the oxygen cascade in mice living on mountaintops, extreme environments for such small organisms. In this JEB-sponsored episode, they discuss the concept of symmorphosis and the evolution of the oxygen cascade.
Trap-jaw ants coordinate tendon and exoskeleton for perfect mandible arc
-AntJaws.png?versionId=3981)
Trap-jaw ants run the risk of tearing themselves apart when they fire off their mandibles, but Greg Sutton & co have discovered that the ants simultaneously push and pull the mandibles using energy stored in a head tendon and their exoskeleton to drive the jaws in a perfect arc.
Hearing without a tympanic ear
-Review.png?versionId=3981)
In their Review, Grace Capshaw, Jakob Christensen-Dalsgaard and Catherine Carr explore the mechanisms of hearing in extant atympanate vertebrates and the implications for the early evolution of tympanate hearing.
Social media
