1988 Fiscal Year Final Research Report Summary

Basic Study on Cerebral Vasospasm

Research Project

Project/Area Number	61570703
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	Cerebral neurosurgery
Research Institution	Nagoya City University
Principal Investigator	TAKAGI Takuji Nagoya City University Medical School, 医学部, 助教授 (70080075)
Co-Investigator(Kenkyū-buntansha)	唐梃洲名古屋市立大学, 医学部, 研究員 MIZUNO Shiro Nagoya City University Medical School, 医学部, 助手 (70190650) NAGAI Hajime Nagoya City University Medical School, 医学部, 教授 (00023747) EN-CHOW Tan Nagoya City University Medical School
Project Period (FY)	1986 – 1988
Keywords	Cerebral vasospasm / Bovine and canine basilar arteries / Human middle cerebral artery / イヌ脳底動脈 / ヒスタミン受容体(H_1、H_2)
Research Abstract	Pharmacological study on the histamine receptors of bovine, canine and human cerebral arteries were carried out as a preliminary study of cerebral vasospasm. The M_2 portion of the human middle cerebral artery was isolated during the autopsy performed 10 hours postmortem period. The arterial strips were cut helically and were fixed in an organ bath containing 20ml of Krebs-Ringer solution areated with 95% O_2 and 5% CO_2. The isometric tension development of arterial strips were measured to evaluate the reactivity of cerebral arteries to histamine, the agonists or antagonists of H_1 or H_2 receptors. 1) Histamine or 2-PEA(H_1 agonist) produced dose-dependent vasoconstriction of the bovine and canine basilar arteries, whereas dimaprit(H_2 agonist) did not induce any vascular response. 2) The dose response curves of bovine or canine basilar ed to the right by tripelennamine(H_1 antagonist). The slopes of the regression line in Schild's plot were 0.94 for both bovine and canine cerebral a … More rteries and pA_2 values of bovine and canine basilar artery were 8.11 and 8.32, respectively. The antagonist effect of tripelennamine on the vascular response to histamine was competitive. 3) The human middle cerebral artery was cumulatively contracted by histamine or 2-PEA, while it was relaxed by dimaprit. Both histamine and dimaprit produced vasorelaxation of human cerebral arteries precontracted by PGF. 4) The dose-response curves were also shifted to the right by tripelennamine and in Schild' plot pA_2 value was 8.99 and the slope was 0.78, which suggested that the antagonist effect of tripelennamine on histamine was not conpetitive. 5) The histamine induced vascular response was influenced by rubbing the intima of human cerebral arteries and it is considered that H_2 receptors mainly exist in the intima of the cerebral artery. 6) The histamine-induced vasoconstriction is suggested to be produced through the effect of second messenger of inositol triphosphate(IP_3) after activation of H_1 receptors. Further investigations will be carried out on alteration of histamine receptors of cerebral artery in dog with experimental subarachnoid hemorrhage. Less