GABAergic innervation of somatostatin-containing neurosecretory cells of the anterior periventricular hypothalamic area: a light and electron microscopy double immunolabelling study.
Double immunolabelling on semithin sections revealed glutamate decarboxylase immunopositive dots surrounding somatostatin-containing cell sections in the rat periventricular hypothalamic area. Up to 12 appositions were observed per cell section with an average number of 2-3 and a unimodal distribution. At the electron microscopical level pre-embedding staining of glutamate decarboxylase showed that most immunoreactive elements consisted of immunolabelled axonal endings. Most of these glutamate decarboxylase immunopositive boutons were found within the neuropil where they frequently made synapses on unidentified dendrites. Some of them were apposed to somatostatin-containing cell bodies that were identified according to the presence of immunolabelled granules using combined immunogold post-embedding staining. In many instances glutamate decarboxylase immunoreactive endings were also found to be involved in synaptic contact with somatostatin-labelled perikarya, or neuronal processes. These contacts provide the morphological basis for a direct GABAergic control of the somatostatin-containing cells regulating the secretion of growth hormone.
D000818:Animals; D005968:Glutamate Decarboxylase / Q000032:analysis; D007032:Hypothalamus, Anterior / Q000166:cytology*; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D009490:Neurosecretory Systems / Q000166:cytology*; D051381:Rats; D011919:Rats, Inbred Strains; D013004:Somatostatin / Q000032:analysis*; D005680:gamma-Aminobutyric Acid / Q000032:analysis*
D013004:Somatostatin; D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase