Ultrastructural changes in pancreatic beta cells treated with NGF and dbcAMP.
Nerve growth factor (NGF) induces morphological and physiological changes in cultured pancreatic beta-cells, including the extension of neurite-like processes. This latter effect is potentiated by dibutyryl cAMP (dbcAMP). beta-cells cultured under these conditions maintain their immunoreactivity to insulin and gamma-amino-butyric acid (GABA). NGF, dbcAMP, and high glucose concentrations also increase the expression of the GABA-synthesizing enzyme glutamic acid decarboxylase-65 in cultured beta-cells. The aim of this work was to study the effect of NGF alone or in combination with dbcAMP on pancreatic beta-cell ultrastructural morphology, after 10 days in culture. We used light microscopy, scanning electron microscopy, and transmission electron microscopy to analyze the modifications in cell surface and neurite-like projections. Morphometric analysis showed that NGF and/or dbcAMP treatment substantially increased the insulin and GABA content in granules and rough endoplasmic reticulum. Given that pancreatic beta-cells express NGF receptors and that NGF is synthesized and secreted by beta-cells, these results further suggest that NGF could have trophic actions on pancreatic hormone synthesis and/or storage.
González del Pliego
M
M
Facultad de Medicina, Depto. de Embriología, Universidad Nacional Autonoma De Mexico (UNAM), Ciudad Universitaria, México D.F., 04510.
Aguirre-Benítez
E
E
Sánchez-Soto
M C
MC
Larrieta
M E
ME
Velázquez-Carranza
A
A
Vidaltamayo
R
R
Meza-Mora
M
M
Zepeda-Rodríguez
A
A
Hernández-Falcón
J
J
Hiriart
M
M
D000818:Animals; D003994:Bucladesine / Q000494:pharmacology*; D002478:Cells, Cultured; D022162:Cytoplasmic Vesicles / Q000737:chemistry / Q000648:ultrastructure; D007328:Insulin / Q000032:analysis; D007515:Islets of Langerhans / Q000737:chemistry / Q000187:drug effects* / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D016253:Microscopy, Immunoelectron; D020932:Nerve Growth Factor / Q000494:pharmacology*; D016501:Neurites / Q000737:chemistry / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D005680:gamma-Aminobutyric Acid / Q000032:analysis
D007328:Insulin; D005680:gamma-Aminobutyric Acid; D003994:Bucladesine; D020932:Nerve Growth Factor