Characterization of the conduction properties in mediterranean fish peripheral nerves

The conduction properties of the I and II spinal nerves from the Mediterranean fish Trachurus trachurus, permanently adapted to a template environment, were studied. These nerves have two types of fibres, myelinic and unmyelinic, correlated with two classes of extracellular compound action potentials, characterised by fast (14 m/s) and slow (3.5 m/s) conduction velocities, as measured at 18° C. The conduction of the nerve impulses is tetrodotoxin sensitive (K d = 22 nM). The temperature dependence of the conduction velocity is bimodal, changing its slope at about 22° C. The Q 10 above 22° C is 1.39 ± 0.02, while below 22° C it is 1.87 ± 0.02. These data will be useful for comparisons with other species adapted to extreme environments.