Hypothalamic galanin‐immunoreactive neurons projecting to the posterior lobe of the rat pituitary: A combined retrograde tracing and immunohistochemical study
J. Comp. Neurol.. 1990-09-22; 299(4): 405-420
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1. J Comp Neurol. 1990 Sep 22;299(4):405-20.
Hypothalamic galanin-immunoreactive neurons projecting to the posterior lobe of
the rat pituitary: a combined retrograde tracing and immunohistochemical study.
Arai R(1), Onteniente B, Trembleau A, Landry M, Calas A.
(1)Département de Cytologie, CNRS UA 1199, Université Pierre et Marie Curie,
To identify the galanin-immunoreactive neurons projecting to the posterior lobe
of the pituitary in the rat hypothalamus, a retrograde tracer (complex of wheat
germ agglutinin-enzymatically inactive horseradish peroxidase-colloidal gold) was
injected into the posterior lobe of the pituitary. Sections of the hypothalamus
were treated with a combination of silver enhancement of retrogradely transported
tracer and immunohistochemistry of galanin. Of the total number of hypothalamic
cells doubly labeled with retrograde tracing and galanin-immunostaining, 56-60%
were found in the supraoptic nucleus, 18-23% in the retrochiasmatic nucleus,
8-10% in the lateral magnocellular portion of the paraventricular nucleus. The
ratio of (number of doubly labeled cells/number of galanin-immunoreactive cells)
in each of the above regions was similar to the ratio of (number of retrogradely
labeled cells/number of Nissl-stained cells) in the supraoptic nucleus. Of all
retrogradely labeled cells in the hypothalamus, 51-56% also contained galaninlike
immunoreactivity.IN CONCLUSION: (1) galanin-immunoreactive fibers in the
posterior lobe of the pituitary originate mainly in the supraoptic nucleus,
retrochiasmatic nucleus, and lateral magnocellular portion of the paraventricular
nucleus, (2) most of galanin-immunoreactive cells in these regions project to the
posterior lobe of the pituitary, and (3) about half the neurons constituting the
hypothalamo-neurohypophyseal system contain galaninlike immunoreactivity.
PMID: 1700801 [Indexed for MEDLINE]