Histaminergic neurons in the sheep diencephalon.
The distribution of histaminergic neurons in the sheep brain was studied by immunohistochemistry by using antibodies raised against histamine. For the first time in this species, the presence of histamine-immunoreactive neurons was described in the caudal diencephalon, around the mammillary bodies, and in the tuberomammillary area. The general pattern of distribution of these neurons was similar to that described previously in other species, i.e., rodents and humans. The distribution in the five neuronal groups described in rodents was not easy to demonstrate in sheep, because the boundaries between each group were not clear. The labeled neurons appeared to form a continuous cell system, as in humans. Numerous histamine-immunoreactive mast cells were found in the habenula and the thalamus. Histamine-immunoreactive fibers were found in almost all of the structures studied. The highest density of fibers was seen in the tuberomammillary area, from which dense bundles of fibers ran rostrally and dorsally along the third ventricle in a parasagittal plane. Numerous immunostained fibers were found close to the wall of the ventricles; some of them appeared to reach the cerebrospinal fluid through the ependymal cell layer. Some fibers were also observed in the optic tract, and the lowest density was found in the supraoptic and paraventricular nuclei. These results should be useful for developing further physiological studies on the role of histaminergic neuronal systems in sheep.
Tillet
Y
Y
Laboratory of Neuroendocrinologie Sexuelle, INRA, Nouzilly, France.
Batailler
M
M
Panula
P
P
D000818:Animals; D000906:Antibodies; D004027:Diencephalon / Q000737:chemistry / Q000166:cytology*; D005260:Female; D006632:Histamine / Q000032:analysis* / Q000276:immunology; D007026:Hypothalamic Area, Lateral / Q000737:chemistry / Q000166:cytology; D009412:Nerve Fibers / Q000737:chemistry; D009474:Neurons / Q000737:chemistry* / Q000648:ultrastructure; D009490:Neurosecretory Systems / Q000737:chemistry / Q000166:cytology; D012756:Sheep / Q000502:physiology*
D000906:Antibodies; D006632:Histamine