UC Davis

Neuroanatomy of OT and AVP in non-human primates OT and AVP immunoreactive cells and fibers in the brain, spinal cord, and pineal gland Atunes and Zimmerman (1978) performed one of the first studies using antisera to AVP, OT, and neurophysins to visualize the OT and AVP system in the hypothalamus of non-human primates. They found that there were OT-immunoreactive cells (-ir) and AVP-ir neurons in the paraventricular nucleus (PVN) and the supraoptic nucleus of the hypothalamus (SON). Additionally, cells containing OT and AVP also contained the neurophysin estrogen-stimulated neurophysin (ESN) and nicotine-stimulated neurophysin (NSN), respectively. These two neurophysins are transporter molecules that are important for the trafficking of OT and AVP molecules after translation (de Bree, 2000). OT-ESN cells and AVP-NSN cells were evenly distributed in the PVN while they were localized within the SON. Subsequent studies examining other non-human primate species found similar results. Currently, OT and AVP neurons have been visualized in three species of macaque (rhesus macaques: Macaca mulatta, crab-eating macaques: Macaca fasciculata, and Japanese macaques: Macaca fuscata)(Atunes and Zimmerman, 1978; Caffé et al., 1989; Ginsberg et al., 1994; Ichimiya et al., 1988; Kawata and Sano, 1982; Sladek and Zimmerman, 1982; Sofroniew et al., 1981), the New World squirrel monkey (Saimiri sciureus) (Sofroniew et al., 1981) and the common marmoset (Callithrix jacchus) (Wang et al., 1997a; Wang et al., 1997b). While there is great similarity between species in the location of OT and AVP cell bodies and fibers, species differences do appear to exist (Table 16.1 details abbreviations; Tables 16.2 and 16.3). It is sometimes difficult to determine whether these species differences are genuine due to the fact that different studies focus on specific brain areas, particular parts of cells, and use different methodologies.