We consider the Klyachko
models of admissible irreducible representations of the group GLn(F) where F is a
non-Archimedean local field of characteristic 0. These are models which
generalize the usual Whittaker model by allowing the inducing subgroup a
symplectic component. We prove the uniqueness of the symplectic models and the
disjointness for unitary representations of the different models. Moreover, for
n ≤ 4 we prove that all unitary irreducible representations admit a Klyachko
model.