Peptides and pseudopeptides derived from tachykinin

A compound selected from those of formula (I):

• ##STR61## in which:
• R.sub.1 is methyl and R.sub.2 is benzyl,
• B represents a residue of an aromatic amino acid,
• A represents
• either a peptide residue of formula:
• ##STR62## in which:
• A.sub.1 represents a bond, a residue 2-azabicyclo[2.2.2]octane-3-carbonyl (Abo), leucine (Leu), .beta.-naphthylalanine (Nal), tryptophan (Trp) or tryptophan protected by Q (Trp(Q)),
• Q representing the radical
• --X--(CH.sub.2)n--R'
• in which
• X represents a bond, --CO-- or --COO--,
• n is an integer from 0 to 10,
• R' is hydrogen, linear or branched (C.sub.1 -C.sub.10) alkyl, benzyl, 9-fluorenylmethyl, --NH.sub.2, --COOH or --COOR" (R"=linear or branched (C.sub.1 -C.sub.8) alkyl),
• A.sub.2 represents an aspartic acid residue (Asp) or glutamic acid residue (Glu),
• A.sub.3 represents a residue 1,2,3,4-tetrahydroisoquinoline-3-carbonyl (Tic), 2-azabicyclo[2.2.2]octane-3-carbonyl (Abo), methylphenylalanine (MePhe), arginine (Arg), arginine protected by nitro (Arg (NO.sub.2)), 6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (Dht), spinacine (Spi), 4-hydroxyproline (Hyp), .beta.-naphthylalanine (Nal) or proline (Pro),
• it being understood that the peptide bond (--CO--NH--) between A.sub.1 and A.sub.2 or between A.sub.2 and B in the case where A.sub.1 is a bond, can be replaced by a pseudopeptide bond chosen from amongst --CH.sub.2 --NH-- and --CH.sub.2 --S--, its and epimers as well as its pharmaceutically-acceptable acid or base addition salts, it being understood that each amino acid of the peptide sequence is optically pure and that the .alpha. carbon of each amino acid can be of D or L configuration.