Mossy cells and different subpopulations of pyramidal neurons are immunoreactive for cocaine- and amphetamine-regulated transcript peptide in the hippocampal formation of non-human primates and tree shrew (Tupaia belangeri)

Our results show that cocaine- and amphetamine-regulated transcript positive neurons in the dentate gyrus of non-human primates are similar to that of the human. Furthermore, in the hippocampal formation of the tree shrew similar cocaine- and amphetamine-regulated transcript-immunoreactive cell-types were observed as in monkeys, supporting their evolutionary relationship with primates. Mossy cells and granule cells are members of a mutual excitatory intrahippocampal circuitry, therefore cocaine- and amphetamine-regulated transcript-immunoreactivity of these neurons in primates and rodents suggests that psychostimulants cocaine and amphetamine may induce memory-related effects at different points of the same excitatory circuitry in the hippocampal formation.