Upregulation of rho A and rho kinase messenger RNAs in the basilar artery of a rat model of subarachnoid hemorrhage.
OBJECTIVE
Rho A, a small guanosine triphosphate-binding protein, and rho kinases have been suggested to play an important role in the agonist-induced myofilament Ca++ sensitization and cytoskeletal organization of smooth-muscle cells. To discover their possible roles in the prolonged contraction seen in cerebral vasospasm, the authors investigated the messenger (m)RNA expressions of rho A and rho-associated kinases alpha and beta in the basilar artery (BA) of a rat double cisternal blood-injection model.


METHODS
An experimental subarachnoid hemorrhage (SAH) was achieved in rats by twice injecting autologous arterial blood into the cisterna magna of each animal. The mRNAs for rho A and rho-associated kinases alpha and beta of the rat BA were analyzed using reverse transcription-polymerase chain reaction (RT-PCR). The cisternal blood injection induced a marked corrugation of elastic lamina and contraction of smooth-muscle cells observed with the aid of light and transmission electron microscopy in the rat BA on Days 3, 5, and 7. Results of the RT-PCR revealed that mRNAs for rho A and rho kinases alpha and beta were expressed in the rat BA and that they were significantly upregulated and reached their peaks on Day 5.


CONCLUSIONS
The mRNA upregulation of these proteins indicates that activation of rho A/rho kinase-related signal transduction pathways is involved in the development of long-lasting contraction of cerebral arteries after SAH.
Miyagi
Y
Y
Department of Neurosurgery, University of Mississippi Medical Center, Jackson, USA.
Carpenter
R C
RC
Meguro
T
T
Parent
A D
AD
Zhang
J H
JH
D000818:Animals; D001488:Basilar Artery / Q000502:physiology; D004195:Disease Models, Animal; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D012234:Rho Factor / Q000378:metabolism*; D015398:Signal Transduction; D013345:Subarachnoid Hemorrhage / Q000378:metabolism / Q000503:physiopathology*; D015854:Up-Regulation; D020301:Vasospasm, Intracranial / Q000378:metabolism / Q000503:physiopathology*; D054460:rho-Associated Kinases
D047908:Intracellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D012234:Rho Factor; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases