[en] The present work is devoted primarily to the study of the solar GRBs as seen by the ISEE-3 satellite, in the energy range between 100 keV and 6.5 MeV. We have also included the cosmic GRB observations from ISEE-3, as a direct comparison for the two phenomena. Thus this thesis comprises 7 chapters: introduction, a chapter providing information on the instruments used, a discussion on the physics of the gamma-ray emission, a chapter describing the cosmic GRBs, and a chapter analysing the solar ones. Finally, we give the conclusions and a summary of our results and indications for the future observations. (orig./UPO)