1. In vitro Contractility Studies of the Rat Middle Cerebral Artery after Stereotactic Gamma Knife Radiosurgery
- Author
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Andras A. Kemeny, O. Major, D.M.C. Forster, A.H. Morice, and J. Jakubowski
- Subjects
Male ,medicine.medical_specialty ,Radiobiology ,Vasodilator Agents ,Gamma knife radiosurgery ,In Vitro Techniques ,Gamma knife ,Radiosurgery ,Contractility ,Isometric Contraction ,medicine.artery ,medicine ,Animals ,Enzyme Inhibitors ,Rats, Wistar ,Ouabain ,business.industry ,Myography ,Cerebral Arteries ,Rats ,NG-Nitroarginine Methyl Ester ,Vasoconstriction ,Middle cerebral artery ,cardiovascular system ,Surgery ,Neurology (clinical) ,Radiology ,business ,circulatory and respiratory physiology ,Myograph - Abstract
The middle cerebral artery (MCA) was irradiated in 94 rats using the Gamma Knife. The vessels receiving 20, 50, 80 and 200 Gy were removed 24 h later and mounted on a myograph. Contractility responses to potassium and prostaglandin (PG) F2 alpha were tested. After precontraction with PGF2 alpha, the relaxant effects of histamine, papaverine, L-arginine and sodium nitroprusside were examined. Other vessels were preincubated with ouabain or N omega-nitro-L-arginine methyl ester before testing with the relaxant agents. After irradiation, the contractile response to maximal potassium and PGF concentrations was diminished, suggesting dose-dependent radiation damage to the contractile mechanism. The normal MCA shows an initial relaxation in the presence of a low K+ concentration, which is Na+, K(+)-ATPase dependent. According to this study, the endothelium-derived relaxation function was suppressed by radiation, suggesting that there is an early change in irradiated vessels, demonstrable by functional studies, which affects both the smooth muscle and endothelial layers.
- Published
- 1996
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