The present invention relates to pyridoindolone derivatives substituted in the 3-position by a heterocyclic group of general formula (I): ##STR00001## in which: R.sub.1 represents a hydrogen atom or a (C.sub.1-C.sub.4)alkyl group; R.sub.2 represents a hydrogen atom or a (C.sub.1-C.sub.4)alkyl group; R.sub.3 represents a thienyl mono- or polysubstituted by a methyl group; or a monocyclic or bicyclic heterocyclic radical chosen from: a pyridyl, an N-oxidopyridinio, a pyrazolyl, an (N-phenyl)pyrazolyl, an (N-halophenyl)pyrazolyl, a furyl, an indolyl, an (N-benzyl)indolyl, an (N-halobenzyl)indolyl, a benzothienyl or a benzofuryl, the said radicals being unsubstituted or substituted one or more times by a halogen atom or a methyl or methoxy group; R.sub.4 and R.sub.5 are identical or different and each independently represent a hydrogen or halogen atom or a hydroxyl, hydroxymethyl, (C.sub.1-C.sub.4)alkyl, trifluoromethyl, C.sub.1-C.sub.4)alkoxy, (C.sub.1-C.sub.4)alkoxycarbonyl or cyano group. Preparation process and application in therapeutics.