Localization of MOR-immunoreactivity in medial part of the neostriatum (St) in coronal sections of the rat brain stained with anti-MOR and GDN method. A: Figure at low magnification illustrating the distribution of MOR-immunoreactivity in rostral part of MrD and the St. MOR-immunoreactivity labelled nerve fibers were densely packed in a moon-like nerve fiber "band" dorsoventrally oriented in the MrD between the St and the GP (arrow indicated by b in A). Patches of MOR-immunoreactivity were localized in the St. B: At higher magnification, fine, punctate MOR-immunoreactivity was seen within the nerve fibers of the "band". C: The fusiform cell body and its processes were also observed among the diffuse, punctate staining in parallel-arranged nerve fibers in the band of the MrD (arrow in C). Several patches of MOR-immunoreactivity were localized in the St, with their extensions dorsoventrally oriented (the arrow indicated by d in A; D). Arrows of b and d refer to areas shown at higher magnification in B and D, Scale bars: A, 500 um; B, C and D, 50 um.