ISSN:
1432-0878
Keywords:
TRH
;
Immunocytochemistry
;
Autoradiography
;
Arcuate nucleus
;
Median eminence
;
Rat
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Immunocytochemical and autoradiographic localization of thyrotropin-releasing hormone (TRH)-and 3H-TRH-binding sites was studied in the arcuate nucleus-median eminence region of the rat. TRH-like immunoreactivity was found in dense granular vesicles (90–140 nm in diameter) in TRH-like immunoreactive nerve fibers and terminals. In the median eminence, the immunoreactive terminals were observed to be in direct contact with the perivascular basal lamina of the portal vessel and to form synaptoid contacts with tanycytes. In the arcuate nucleus, the immunoreactive terminals were often found to form axosomatic and axo-axonic, and/or axo-dendritic synapses. The uptake of tritiated TRH into the nerve fibers and terminals of the median eminence was also observed by autoradiography and the distribution and localization of silver grains in them were analyzed quantitatively by circle analysis. Thirty minutes after intraventricular infusion of 3H-TRH, radioactive labeling occurred in type-2 and 3-nerve fibers and terminals containing dense granular vesicles in the median eminence. It is therefore suggested that the neurons labeled after 3H-TRH infusion possess certain functions as physiological recognition sites or receptors for TRH.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00211469
