TY - JOUR
T1 - Effects of short- and long-term rat hind limb immobilization on spinal cord insulin-like growth factor-I and its receptor
AU - Suliman, Isam A.
AU - Lindgren, J. Urban
AU - Elhassan, Adlan M.
AU - Diab, Khaled M.
AU - Adem, Abdu
N1 - Funding Information:
This work was supported by grants from the AO Foundation, Switzerland; the Swedish Medical Research Council, KI Fonder, and Loo och Hans Ostermans Stiftelse.
PY - 2001/8/31
Y1 - 2001/8/31
N2 - 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.
AB - 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.
KW - Autoradiography
KW - Cholinergic receptors
KW - Skeletal muscle
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U2 - 10.1016/S0006-8993(01)02564-1
DO - 10.1016/S0006-8993(01)02564-1
M3 - Article
C2 - 11520489
AN - SCOPUS:0035979805
SN - 0006-8993
VL - 912
SP - 17
EP - 23
JO - Brain Research
JF - Brain Research
IS - 1
ER -