  In this paper, we study the chiral symmetry restoration in the hadronic
spectrum in the framework of generalised Nambu-Jona-Lasinio quark models with
instantaneous confining quark kernels. We investigate a heavy-light quarkonium
and derive its bound-state equation in the form of a Schroedingerlike equation
and, after the exact inverse Foldy-Wouthuysen transformation, in the form of a
Diraclike quation. We discuss the Lorentz nature of confinement for such a
system and demonstrate explicitly the effective chiral symmetry restoration for
highly excited states in the mesonic spectrum. We give an estimate for the
scale of this restoration.
