Theoretical research on electronic properties in mesoscopic condensed matter systems has focused primarily on the electron charge freedom degrees, while its corresponding spin freedom degrees have not yet received the same attention. Nevertheless nowadays there has been an increment in the number of electron spin-related experiments showing unique possibilities for finding novel mechanisms of information processing and transmission, opening ample fields of opportunities in the theoretical developed of new models. In this spirit we have calculated the resonant tunneling characteristics curves in double-barrier heterostructures of GaAs-Ga1-x AlxAs under external stress and considering two charges with spin half. The resonant tunneling study has been carried out by means of the diagrammatic techniques for non equilibrium processes following the model proposed by Keldysh also a simple one-band tight-binding Hamiltonian is adopted in the theoretical framework. We have compared our results of the spin-tunneling with previous ones reported in literature.