A mathematical model of electrical transduction events in crayfish stretch receptors

Crayfish (A. astacus) stretch receptors are an example of invertebrate muscle stretch receptors. They show strong homology to mammalian muscle spindles and bi-polar neurons in D. melanogaster, which are typical, non-ciliated, multi-dendritic, afferent neurons. Such receptors are observed in many species and perform an important sensory role. However, they are poorly characterised. A previous bio-mechanical and behavioural model of A. astacus stretch receptors was produced, using the principles of elasticity and tension in a spring to describe the adaptation of a mechano-sensory ending. This model has proven to be a reliable predictor of the changing mechano-sensory currents in the receptor under a stretch protocol. Through a re-implementation of the original model, from the relationships therein encoded, and via the incorporation of additional descriptions of voltage-gated channels commonly present in neurons, the model was updated to present a more complete picture of the initiation of the receptor potential of mechano-receptor in the presence of a stretching stimulus. It was shown that the addition of simple voltage-dependent sodium and potassium currents to the initial mechano-sensitive sodium current accounted for most of the initial stretch response of the receptor. This model has the potential for expansion to fully describe the behaviour of non-ciliated mechano-sensors and predict the sub-cellular mediators of mechanotransduction.