The present invention relates to compounds of the formula (I):
##STR1##
wherein:
Het represents a heterocyclic residue selected from:
##STR2##
where the dotted line in (b) represents an optional double bond;
A completes a fused pyridine ring; and
B completes a fused benzene or pyridine ring.
The compounds are of particular use in the treatment or prevention of
depression, anxiety, pain, inflammation, migaine, emesis or postherpetic
neuralgia.
