Extracellular adenosine 5'-triphosphate mediates oxidative stress and cell death under cadmium stress by nitric oxide

Cadmium (Cd) is one of the most bio-toxic heavy metals. Extracellular adenosine 5'-triphosphate (ex ATP) is an important signaling molecule involved in regulating physio-logical processes in cells. This study showed that Cd ions (Cd²⁺) increased oxidative stress and death level of Nicotiana tabacum L. suspension cells in a concentration-dependent manner. Conversely, application of exogenous ATP effectively alleviated the increase in Cd²⁺-induced oxidative stress and cell death. Furthermore, similar to the above-mentioned mitigation effects of exogenous ATP, SNP (a nitric oxide donor) also alleviated the increase in Cd²⁺-induced oxidative stress and cell death levels. Moreover, NO synthesis inhibitor (L-NAME) partially relieved the alleviating effects of exogenous ATP. These results indicate that ex ATP regulates Cd-induced oxidative stress and cell death by NO.