Laser diffraction used to monitor strain in mechanoreceptors ofJasus verreauxi

Summary Laser diffraction patterns from crayfish abdominal mechanoreceptors have been observed and the corresponding sarcomere lengths calculated and then correlated with sensory nerve discharge frequencies.Our thanks are due to the Australian Research Grants Committee for provision of the lasers and camera, to Dr.K. S. Imrie for the design of the interfacing cards, to ProfessorP. Mason and ProfessorR. E. Aitchison for their encouragement and advice, and toI. Paterson andC. March for constructing the equipement.     

The physiological effects of ionic lanthanum on the insect blood-brain barrier

Summary Lanthanum had a small effect on the barrier, but did not significantly increase its sodium or patossium permeability. There was no effect on nerve conduction unless the barrier was deliberately damaged. The results lend confidence to the use of lanthanum as an extracellular tracer.