Functional topography of the rat hypothalamic dopamine neuron systems: Retrograde tracing and immunohistochemical study

Abstract

The origins of the dopamine (DA)-containing nerve terminals in the external layer of the median eminence and in the neurointermediate pituitary were determined in rats by a combination of retrograde labeling with wheat germ agglutinin (WGA) and immunohistochemistry for tyrosine hydroxylase (TH). Biotinylated WGA (b-WGA) was injected into the posterior pituitary (group 1) and into the median eminence (group 2). In group 1 animals, all the magnocellular neurons of the paraventricular, supraoptic, and accessory nuclei, and many parvicellular neurons in the rostral periventricular region (RPR) were labeled with WGA. In group 2 animals, many neurons were labeled in the arcuate nucleus and the RPR, and in a small population of the preoptic-septal region. In group 1 animals, about 39% of TH neurons in the RPR were labeled with WGA, whereas only a few TH neurons (1%) in the arcuate nucleus were labeled with WGA. In group 2 animals, on the contrary, almost all TH neurons (73%) in the arcuate nucleus carried WGA, whereas in the RPR, only some of the TH neurons (19%) were labeled with WGA. It is concluded that DA neurons involved in the hypothalamic-anterior pituitary axis are located in the arcuate nucleus; those involved in neuro-intermediate lobe function in the RPR.

Restorative effect of insulin-like growth factor-I gene therapy in the hypothalamus of senile rats with dopaminergic dysfunction

“…25 The A 14 DA neurons are mainly located within the PaV and PeV nuclei, with a few scattered DA neurons in the anterior ventromedial hypothalamic area. 25,26 The A 12 area and its corresponding axon terminals constitute the TIDA system, whereas the A 14 area and its fibers are known as the periventricular dopaminergic system. Both systems regulate PRL secretion by exerting a tonic inhibitory control on both PRL secretion and lactotroph proliferation.…”

Spatiotemporal patterns of secretomotor neuron generation in the parvicellular neuroendocrine system 1Published on the World Wide Web on 3 June 1997. 1

“…First, because the retrograde tracer was injected into the general circulation, it may be taken up by axon terminals in circumventricular organs other than the median eminence. Specifically, some neurons in and around the periventricular zone may project to the area postrema, subfornical organ, or vascular organ of the lamina terminalis, and a small population of dopaminergic neurons outside the ARH that projects to the intermediate lobe of the pituitary was probably labeled [29], although the latter may be considered a special class of neuroendocrine motoneurons. And second, TH is clearly expressed is a subset of magnocellular neurosecretory vasopressinergic neurons in the PVH (and supraoptic nucleus) (see [16,32]).…”

“…6e14). Other e14 GRH PCNs were observed in the ARH through the level of the dorsomedial nucleus (atlas levels [28][29][30], and two actually lie within the ventral part of the dorsomedial nucleus (see atlas levels 30 and 31, Fig. 6e14).…”

Galanin Immunoreactivity in Mouse Basal Forebrain: Sex Differences and Discrete Projections of Galanin-Containing Cells beyond the Blood-Brain Barrier

“…The present results in mice are consistent with these reports. Injection of HRP or wheat germ agglutinin into the pituitary in rats resulted in retrograde labeling in SOR, SON, magnocellular PVN and accessory magnocellular neurosecretory cell groups in the basal forebrain [7, 38, 39]. However, injection of these tracers into the median eminence in rats resulted in uptake in the OVLT, periventricular and preoptic areas, parvicellular PVN and ARC without any noticeable labeling in the magnocellular neurons in the SON, SOR, PVN and the accessory magnocellular structures [40, 41].…”