Before the experimental procedure, crabs were anesthetized by chilling (5 min), and the two (left and right) jaw muscles (50 mg) of individual specimens were rapidly removed and placed on a Petri dish containing cold incubation buffer adapted to N. granulata (SFC): 350 mM NaCl, 10 mM KCl, 25 mM CaCl2, 10 mM MgCl2, 8.8 mM H3BO3, plus 10 mM HEPES and 1% PMSF, pH 7.8. There was no death or body-mass variation during the experimental periods. Radioactivity was measured in an LKB Wallac scintillation counter. All counts contained an internal standard curve for quench correction.