ISSN:
1432-0878
Keywords:
Nucleus lateralis tuberis
;
Innervation of the pituitary
;
Gillichthys
;
Ultrastructure
;
Histochemistry
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary The innervation of the pituitary gland of the teleost fish Gillichthys mirabilis was studied with light and electron microscopy in order to determine its nature and distribution. Two types of neurosecretory fibers (“A” and “B”) are present in the adenohypophysis. Type “A” fibers containing elementary neurosecretory granules, 1,500–1,600 Å in diameter, perforate the basement membrane in the neurointermediate lobe and make synaptoid contacts with MSH cells. Type “B” fibers containing large granulated vesicles (LGV), 900–1,000 Å in diameter, perforate the basement membrane in all lobes of the pituitary gland and terminate in direct contact with the several adenohypophysial cell types. At the electron-microscope level, LGV from type “B” fibers show a positive reaction to zinc iodide-osmium tetroxide (ZIO) impregnation. Reserpine treatment resulted in a depletion of their dense cores if osmium tetroxide was used as the only fixative, whereas double fixation with aldehydes and osmium tetroxide did not reveal appreciable changes. Yellow-to-green fluorescent fibers were detected in the pituitary gland after the Falck-Hillarp technique at sites corresponding approximately to the location of type “B” fibers, strongly suggesting the monoaminergic nature of the latter. After hypophysectomy, medial and lateral neurons of the nucleus lateralis tuberis (NLT) undergo retrograde degeneration. This finding, together with the morphological and cytochemical similarities of the LGV in NLT neurons and those in the type “B” fibers, suggests that the fibers originate from certain NLT neurosecretory neurons.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00330101
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