Rho kinase regulates neurite outgrowth of hippocampal neurons via calcium dependent cytoskeleton regulation.
OBJECTIVE
To investigate whether calcium is involved in downstream signal transduction in neurite outgrowth regulated by Rho kinase.


METHODS
In vitroprimary hippocampal neurons were cultured and treated with Rho kinase agonist (LPA) or antagonist (Y-27632). Then, the cytoskeleton and neurite outgrowth were observed. After addition of calcium antagonist BAPTA/AM to reduce intracellular calcium, the cytoskeleton distribution and neurite outgrowth were observed.


RESULTS
The activation or inhibition of Rho kinase could significantly alter the number and length of neurites of hippocampal neurons. Rho kinase regulated the cytoskeleton to regulate the neurite outgrowth, and LPA could significantly increase intracellular calcium. After BAPTA/AM treatment, the length and branch number of neurites of neurons reduced markedly. BAPTA/AM was able to reduce intracellular calcium and decrease neuronal cytoskeleton. Treatment with both BAPTA/AM and LPA could stop the retraction of neurites, but the length and branch number of neurites remained unchanged after treatment with Y-27632 and LPA.


CONCLUSIONS
Calcium may affect the cytoskeleton arrangement to regulate neurite outgrowth, and calcium is involved in the downstream signal transduction of Rho kinase regulated neurite outgrowth of hippocampal neurons.
Department of Orthopedics, The First Affiliated Hospital of Jinan UniversityGuangzhou 510630, China; Department of Anatomy, Medical College of Jinan UniversityGuangzhou 510630, China.
Zhisheng
Z
Ji
Department of Orthopedics, The First Affiliated Hospital of Jinan UniversityGuangzhou 510630, China; Department of Anatomy, Medical College of Jinan UniversityGuangzhou 510630, China.
Zhenbin
Z
Cai
Department of Orthopedics, The First Affiliated Hospital of Jinan UniversityGuangzhou 510630, China; Department of Anatomy, Medical College of Jinan UniversityGuangzhou 510630, China.
Jifeng
J
Zhang
Department of Orthopedics, The First Affiliated Hospital of Jinan University Guangzhou 510630, China.
Nannuan
N
Liu
Department of Orthopedics, The First Affiliated Hospital of Jinan University Guangzhou 510630, China.
Jing
J
Chen
Department of Orthopedics, The First Affiliated Hospital of Jinan UniversityGuangzhou 510630, China; Department of Anatomy, Medical College of Jinan UniversityGuangzhou 510630, China.
Minghui
M
Tan
Department of Orthopedics, The First Affiliated Hospital of Jinan University Guangzhou 510630, China.
Hongsheng
H
Lin
Department of Anatomy, Medical College of Jinan University Guangzhou 510630, China.
Guoqing
G
Guo
Rho kinase; calcium; hippocampal neuron; neurite outgrowth; rat