While your cat might respond to being tickled, chances are its more of a reflex than a tickle response. Just like humans, some cats may be more ticklish than others. There are plenty of cats (and dogs, as well as other animals) who have thumped a hind leg when they were scratched in the right place.
Much like humans, animals will also instinctively try to escape from unpleasant stimuli, so if you tickle or scratch your cat and he hates it, you will probably know it when he tries to flee. Some cats enjoy being tickled, scratched, or pet on their bellies and/or chin.