Hermes-Lima, M. and Storey, K.B. 1995. Antioxidant defenses and metabolic depression in a pulmonate land snail. Am. J. Physiol. 268, R1386-R1393.


Marcelo Hermes-Lima and Kenneth B. Storey

During arousal from estivation oxygen consumption by land snails Otala lactea increases severalfold. To determine whether snails prepared for an accompanying rise in the rates of oxyradical generation by altering their antioxidant defense mechanims, changes in the activities of antioxidant enzymes and lipid peroxidation products were quantified in foot and hepatopancreas of control, 30 d estivating, and aroused snails. Compared with controls, estivating O. lactea showed significant increases in the activities of foot muscle superoxide dismutase (SOD) (increasing by 56-67%), catalase (51-72%), and glutathione S-transferase (79-108%), whereas in hepatopancreas SOD (57-78%), and glutathione peroxidase (93-144%) increased. Within 40 min after arousal began, hepatopancreas GPX activity had returned to control values, but SOD showed a further 70% increase in activity but then returned to control levels by 80 min. Estivation had no effect on total glutathione (GSH + 2 GSSG) concentrations in tissues but GSSG content had increased about 2-fold in both organs of 30-day dormant snails. Lipid peroxidation (quantified as thiobarbituric acid reactive substances) was significantly enhanced at the onset of arousal from dormancy indicating that oxidative stress and tissue damage occurred at this time. The data suggest that antioxidant defenses in snail organs are increased while in the hypometabolic state as a preparation for oxidative stress during arousal.