Abstract
In this study we investigated changes in the spinal cord insulin-like growth factor-I peptide (IGF-I) and its receptors (IGF-IR) after hind limb immobilization for 5 days, 2, 4, and 8 weeks. Moreover, effects on IGF-I and nicotinic cholinergic receptors (nAChRs) in two types of skeletal muscle were also investigated. IGF-I levels were measured by radioimmunoassay (RIA) whereas IGF-IR and nAChRs were measured by quantitative receptor autoradiography. Spinal cord IGF-I levels decreased significantly after 5 days, 2 and 4 weeks of immobilization, whereas IGF-IR increased significantly after 4 and 8 weeks compared to controls. In skeletal muscles, nAChRs increased significantly after 5 days and 2 weeks in the soleus (SOL) and tibialis anterior (TIB) muscles, respectively, and continued up to 8 weeks in both muscles. IGF-I concentration decrease significantly after 4 and 8 weeks in the SOL and TIB muscles, respectively. Despite the normal levels of IGF-I in both muscles at the early time points (5 days and 2 weeks), low levels of IGF-I were observed concurrently in the spinal cord ipsilateral to the immobilized limb. Our findings suggest that the early decrease in the IGF-I level and the late uppregulation in the IGF-IR in the spinal cord might represent a nervous system response to disuse.
Original language | English |
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Pages (from-to) | 17-23 |
Number of pages | 7 |
Journal | Brain Research |
Volume | 912 |
Issue number | 1 |
DOIs | |
Publication status | Published - Aug 31 2001 |
Externally published | Yes |
Keywords
- Autoradiography
- Cholinergic receptors
- Skeletal muscle
ASJC Scopus subject areas
- General Neuroscience
- Molecular Biology
- Clinical Neurology
- Developmental Biology