N-aryl piperidine compounds as 5HT.sub.1B antagonists

N-arylpiperidine compounds selected from those of formula I:

• ##STR11## wherein:
• m represents 1 to 5 inclusive;
• n represents 1 or 2;
• R represents hydrogen, straight-chain or branched (C.sub.1 -C.sub.5)alkyl, or aralkyl in which the alkyl moiety contains 1 to 5 carbon atoms inclusive in straight or branched chain;
• E represents hydrogen or methyl;
• Ar represents:
• ##STR12## X being hydrogen or halogen and A represents:
• ##STR13## wherein:
• X.sub.1, X.sub.2, X.sub.3, and X.sub.4, which may be identical or different,
• each represents hydrogen or halogen, (C.sub.1 -C.sub.5)alkyl, or (C.sub.1 -C.sub.5)alkoxy, each of which is straight-chain or branched, trifluoromethyl, hydroxy, cyano, or nitro, or ##STR14## wherein :
• R.sub.1, R.sub.2, and R.sub.3, which may be identical or different, each represents hydrogen or straight-chain or branched (C.sub.1 -C.sub.5)alkyl, and R.sub.4 represents a straight-chain or branched (C.sub.1 -C.sub.5)alkyl, or
• a pair of X.sub.1, X.sub.2, X.sub.3, and X.sub.4 adjacent to one another form, together with the carbon of the phenyl to which they are bonded, a 5-membered or 6-membered ring comprising atoms selected from carbon, oxygen, nitrogen, and sulphur,
• where they exist in the form of a racemic mixture or in the form of optical isomers,
• and physiologically-tolerable acid addition salts thereof.