Nitric Oxide (NO) generation in molluscs

GONZÁLEZ, P.M. AND PUNTARULO, S.

San José

Conferencia; First International Conference on Oxidative Stress in Aquatic Ecosystems; 2012

Centro de investigaciones biológicas del noroeste, S.C.

The aim of this work was to characterize the nitric oxide (NO) generation under physiological conditions in bivalves and limpets. Digestive gland of bivalves (Mya arenaria from the Wadden Sea, Laternula elliptica from Antarctica, Mytilus edulis platensis from the Argentinean Sea) and limpets (Nacella concinna intertidal and subtidal from Antartica, Nacella deaurata and Nacella magellanica from the Beagle Channel) were employed. Nitrate (NO3-) and nitrite (NO2-) content was measured by the Griess reaction. The NO2- content was under the detection levels in all the studied species. The NO3- content was significantly different between the animals tested (613 ± 38, 73 ± 7, 148 ± 13 and 102 ± 10 pmol/mg FW in M. arenaria, L. elliptica, N. concinna intertidal and N. concinna subtidal, respectively). The NO content, assessed by electron paramagnetic resonance (EPR), was 99 ± 3, 29 ± 2, 9 ± 1, 25 ± 3, 22 ± 2, 91 ± 4 and 62 ± 7 pmol/mg FW in M. arenaria, L. elliptica, M. edulis platensis, N. concinna intertidal, N. concinna subtidal, N. magellanica and N. deaurata, respectively. NO production was followed by EPR in the presence of LArginine and NADPH to assess a possible role for the enzyme nitric oxide synthase (NOS)-like in these animals. In the bivalves, M. arenaria and L. elliptica, the maximum NOS-like activity was 12.9 ± 0.2 and 12.0 ± 0.4 pmol/mg FW min, respectively. In the limpets, N. concinna intertidal and subtidal, the maximum NOS like activity was 3.4 ± 0.3 and 4.7 ± 0.6 pmol/mg FW min, respectively. These results showed that NO species were detected under physiological conditions in all the organisms and NOS-like activity appeared as a possible physiological source of NO generation, besides others. Further studies will allow to detail the relevance of this pathway.