The present invention is directed to 1,2,3,4,10,10a,-hexahydropyrazino[1,2-a] indole derivatives as well as pharmaceutically acceptable salts, solvates and esters thereof, wherein R.sup.1 to R.sup.8 have the significance given in claim 1 be used in the form of pharmaceutical preparations for the treatment or prevention of disorders of the central nervous system, damage to the central nervous system, cardiovascular disorders, gastrointestinal disorders, diabetes insipidus, obesity and sleep apnea.