European Journal of Anatomy

Official Journal of The Spanish Society of Anatomy
Cover Volume 4 - Number 3
Eur J Anat, 4 (3): 185-190 (2000)

Insulin-like growth factor 1-receptor (IGF-1R) in developing and adult human dorsal root ganglia

Germana P., San Jose I., Esteban I., Vazquez M.T., Vega J.A.

Depto. Morfologia/Biologia Celular, Facultad de Medicina, C/ Julián Claveria, s/n, 33006 Oviedo, Spain

ABSTRACT Insulin-like growth factors (IGFs) promote neurite outgrowth in cultured sensory neurons that binding to IGF type 1 receptor (IGF-1R) and seem to be involved in the pathogenesis of some metabolic and toxic peripheral neuropathies coursing with altered sensitivity. However, the distribution of IGF-1R in the human sensory peripheral nervous system is unknown. In this study, we used light immunohistochemistry to analyse the occurrence and localization of IGF-1R in developing (6 to 22 weeks of estimated gestational age, e.g.a.) and adult (age range 25-41 years) human dorsal root ganglia (DRG). In human embryos (6-8 weeks e.g.a.) and young foetuses (9 weeks e.g.a.), most neurons (84%, 92%, and 83%, respectively) displayed IGF-1R immunoreactivity (IR). In older foetuses (12 and 22 weeks e.g.a.), the number of immunoreactive neurons decreased progressively (78 and 68%, respectively) reaching values similar to those observed in adults (64%). The subpopulation of adult primary sensory neurons showing IGF-1R IR covered the entire size range, but the neurons were mainly small. Furthermore, in adults all satellite glial cells and Schwann cells were immunoreactive. The present results suggest a role for IGF-1R in the differentiation and maturation of primary sensory neurons, and in the maintenance of a subset of them in adulthood, as well as in the control of peripheral glial cells (Schwann and satellite glial cells). These findings might serve as a basis for future studies in pathologic DRG, in which IGF-1R or its ligands may be involved.

Keywords: somatomedin C receptor, adult, article, cell differentiation, cell maturation, cell size, embryo, fetus, glia cell, human, human tissue, immunohistochemistry, immunoreactivity, protein localization, Schwann cell, sensory nerve cell, spinal cord nerve cell, spinal ganglion

European Journal of anatomy
ISSN 2340-311X (Online)