TY - JOUR
T1 - Calcium influx pathways in rat CNS pericytes
AU - Kamouchi, Masahiro
AU - Kitazono, Takanari
AU - Ago, Tetsuro
AU - Wakisaka, Masanori
AU - Ooboshi, Hiroaki
AU - Ibayashi, Setsuro
AU - Iida, Mitsuo
N1 - Funding Information:
This study was supported by Research Grants for Cardiovascular Diseases (11-1) from the Ministry of Health, Labour and Welfare of Japan.
Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2004/7/26
Y1 - 2004/7/26
N2 - In central nervous system (CNS), pericytes have been proposed to play a role in broad functional activities including blood-brain barrier, microcirculation, and macrophage activity. However, contractile responses and Ca2+ signaling in CNS pericytes have not been elucidated. The aim of the present study is to investigate contractility and Ca2+ influx pathway in CNS pericytes. CNS pericytes were cultured from rat brain. Contraction of the pericytes in response to various stimuli was evaluated by the change in surface area measured by a light microscope with a digital camera. Reverse transcription and polymerase chain reaction (RT-PCR) was performed to examine the expression of mRNA of α-smooth muscle actin. Intracellular Ca2+ was measured using fura-2 fluorescence spectroscopy. A23187 (Ca2+ ionophore), high external K+ (4×10 -2 mol/l), endothelin-1, and serotonin induced contraction of CNS pericytes. RT-PCR analysis revealed the expression of α-smooth muscle actin in CNS pericytes. Cytosolic Ca2+ ([Ca2+]i) increased after application of high concentration of external K+, tetraethylammonium, and charybdotoxin, which was inhibited by nicardipine and removal of external Ca2+. Angiotensin-II, serotonin, acetylcholine, ATP, and endothelin-1 caused biphasic response in [Ca2+]i. In response to these agents, [Ca2+]i rapidly increased and then decayed to a relatively constant Ca2+ plateau. The Ca2+ plateau was partially inhibited by nicardipine and completely abolished by omission of external Ca2+. After intracellular Ca2+ store was depleted by the removal of external Ca2+ and addition of thapsigargin, reapplication of external Ca2+ evoked increases in [Ca 2+]i. These results indicate that CNS pericytes express mRNA of α-smooth muscle actin and possess contractile ability. In CNS pericytes, resting membrane potential is regulated by large conductance Ca 2+-activated K+ channels and Ca2+ enters into the cells via L-type voltage-dependent Ca2+ channels, agonist-activated Ca2+ permeable channels, and capacitative Ca 2+ entry pathways.
AB - In central nervous system (CNS), pericytes have been proposed to play a role in broad functional activities including blood-brain barrier, microcirculation, and macrophage activity. However, contractile responses and Ca2+ signaling in CNS pericytes have not been elucidated. The aim of the present study is to investigate contractility and Ca2+ influx pathway in CNS pericytes. CNS pericytes were cultured from rat brain. Contraction of the pericytes in response to various stimuli was evaluated by the change in surface area measured by a light microscope with a digital camera. Reverse transcription and polymerase chain reaction (RT-PCR) was performed to examine the expression of mRNA of α-smooth muscle actin. Intracellular Ca2+ was measured using fura-2 fluorescence spectroscopy. A23187 (Ca2+ ionophore), high external K+ (4×10 -2 mol/l), endothelin-1, and serotonin induced contraction of CNS pericytes. RT-PCR analysis revealed the expression of α-smooth muscle actin in CNS pericytes. Cytosolic Ca2+ ([Ca2+]i) increased after application of high concentration of external K+, tetraethylammonium, and charybdotoxin, which was inhibited by nicardipine and removal of external Ca2+. Angiotensin-II, serotonin, acetylcholine, ATP, and endothelin-1 caused biphasic response in [Ca2+]i. In response to these agents, [Ca2+]i rapidly increased and then decayed to a relatively constant Ca2+ plateau. The Ca2+ plateau was partially inhibited by nicardipine and completely abolished by omission of external Ca2+. After intracellular Ca2+ store was depleted by the removal of external Ca2+ and addition of thapsigargin, reapplication of external Ca2+ evoked increases in [Ca 2+]i. These results indicate that CNS pericytes express mRNA of α-smooth muscle actin and possess contractile ability. In CNS pericytes, resting membrane potential is regulated by large conductance Ca 2+-activated K+ channels and Ca2+ enters into the cells via L-type voltage-dependent Ca2+ channels, agonist-activated Ca2+ permeable channels, and capacitative Ca 2+ entry pathways.
UR - http://www.scopus.com/inward/record.url?scp=3042789099&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=3042789099&partnerID=8YFLogxK
U2 - 10.1016/j.molbrainres.2004.03.008
DO - 10.1016/j.molbrainres.2004.03.008
M3 - Article
C2 - 15249134
AN - SCOPUS:3042789099
VL - 126
SP - 114
EP - 120
JO - Molecular Brain Research
JF - Molecular Brain Research
SN - 0006-8993
IS - 2
ER -