Compounds of formula (I), or a salt or prodrug thereof, wherein Z represents an optionally substituted five-membered heteroaromatic ring selected from furan, thiophene, pyrrole, oxazole, thiazole, isoxazole, isothiazole, imidazole, pyrazole, oxadiazole, thiadiazole, triazole, and tetrazole; E represents a chemical bond or a straight or branched alkylene chain containing from 1-4 carbon atoms; Q represents a straight or branched alkylene chain containing from 1-6 carbon atoms; T represents nitrogen or CH; R.sup.1 represents aryl(C.sub.1-6)alkyl or heteroaryl(C.sub.1-6)alkyl, either of which groups may be optionally substituted; and R.sup.2 represents hydrogen or C.sub.1-6 alkyl are selective agonists of 5-HT.sub.1 -like receptors, being potent agonists of the human 5-HT.sub.1D.alpha. receptor subtype whilst possessing at least a 10-fold selective affinity for the 5-HT.sub.1D.alpha. receptor subtype relative to the 5-HT.sub.1D.beta. subtype; they are therefore useful in the treatment and/or prevention of clinical conditions, in particular migraine and associated disorders, for which a subtype-selective agonist of 5-HT.sub.1D receptors is indicated, whilst eliciting fewer side-effects, notably adverse cardiovascular events, than those associated with non-subtype-selective 5-HT.sub.1D receptor agonists. ##STR1##