Nuestro último artículo, aceptado en Aquaculture

Intracellular changes in Ca²⁺, K⁺ and pH after sperm motility activation in the European eel (Anguilla anguilla): preliminary results

V. Gallego, F. Martínez-Pastor, I. Mazzeo, D.S. Peñaranda, M.P. Herráez, J.F. Asturiano and L. Pérez

Although it is widely accepted that osmolality and ion fluxes are the main factors triggering sperm motility in fish, a complex universal mechanism for sperm motility activation does not exist in fish, and studies of marine fish species are even more scarce. Therefore, the main goal of this study was to estimate the intracellular variations in the main ions involved in sperm activation for the first time in European eel, in order to provide additional new data about this little-known process.

It was observed that levels of intracellular Ca²⁺ and K⁺ sperm ions increased significantly 30 s after the hyperosmotic shock compared to baseline levels, and remained at this level until 120 s post-activation. In contrast, the intracellular pH remained constant during the first 30 s, and decreased gradually at 60 and 120 s postactivation. Our data agree with the current main theory for explaining motility activation in marine fish, in which internal fluctuations of Ca²⁺ and K⁺ seem to participate in sperm activation. In addition, fluorescent images showed that both Ca²⁺ and K⁺ were concentrated in the apical area of the sperm head, which corresponds to the location of the eel sperm mitochondria, suggesting this organelle plays an important role in sperm motility activation.