The human lateral tuberal nucleus: Immunohistochemical characterization and analogy to the rodent PV1-nucleus

Abstract

A B S T R A C TThe lateral tuberal nucleus (LTN) is a hypothalamic region that has been identified with certainty only in humans and primates. It is composed of three small round globular units which protrude the basal surface of the brain along the optic tract. The function of the LTN is unknown. Recently, a tiny, parvalbumin-positive (PV1) nucleus was detected in the lateral hypothalamus of rodents. Like the human LTN, the rodent PV1-nucleus is subdivided into three units and lies along the optic tract. To ascertain whether the human LTN and the rodent PV1-nucleus could be considered as homologous structures not only based on their topographic location but also because of their neurochemical characteristics, we subjected tissue samples from humans, rats and mice to immunohistochemical analysis for a panel of neural markers. The human LTN was intensely immunoreactive for somatostatin and FF1, but only weakly so or not at all for parvalbumin, calbindin and calretinin. The rodent PV1-nucleus was intensely immunoreactive for parvalbumin but was not immunoreactive for either somatostatin, a surrogate for human FF1, calbindin or calretinin. Hence, using these neural markers, it was not possible to demonstrate a neurochemical homology between the human LTN and the rodent PV1-nucleus.

Expression of the calcium binding proteins Necab-1,-2 and -3 in the adult mouse hippocampus and dentate gyrus

“…Polyclonal antibodies against calbindin D-28k, parvalbumin and calretinin were received from Swant (Marly, Switzerland). These antibodies and the immunhistochemical technique have been described previously (Gerig and Celio 2007;Meszar et al, 2012).…”

Gene expression analysis in the parvalbumin‐immunoreactive PV1 nucleus of the mouse lateral hypothalamus

“…On the basis of its topography and neuroanatomy, the lateral tuberal nucleus (LTN) in primates was previously suggested to correspond to the PV1 nucleus in rodents (Gerig & Celio, 2007), although neurochemical homologies have not yet been demonstrated. Indeed, LTN neurons do not express Pvalb but can be revealed with antibodies to somatotostatin (Fig.…”

“…Indeed, LTN neurons do not express Pvalb but can be revealed with antibodies to somatotostatin (Fig. 6A) (Gerig & Celio, 2007). We prepared M. fascicularis antisense RNA probes to two genes: one marker of the rodent PV1 nucleus, Serpini1, and one gene encoding vesicular glutamate transporter VGlut1, Slc17a7 (note that only Slc17a6, not Slc17a7, was found to be expressed in the mouse PV1, but, unfortunately, we were unable to obtain probe for Macaca Slc17a6).…”

The anatomy of the Göttingen minipig hypothalamus

“…However, over the years the medial tuberal nucleus, the terete nucleus and parvalbumin-positive nucleus in the rat have been considered to be homologs to the LTu in primates (Saper, 1990;Simerly, 2004;Gerig and Celio, 2007). Unlike the surrounding lateral hypothalamic area, the minipig and primate LTu, and the proposed homologous nuclei in the rat, are devoid of AChE, CR and ORX reactive cells (Elias et al, 1998;Gerig and Celio, 2007;Paxinos and Watson, 2007;Paxinos et al, 2009a). The monkey LTu shares a less intimate relationship with the tuberomammillary nucleus than it does in man.…”