Korean J Anesthesiol.  2000 Feb;38(2):340-347. 10.4097/kjae.2000.38.2.340.

Effects of Nitric Oxide Synthase Inhibitior on Energy Metabolism in Acute Ischemic-Reperfused Cat Brain: Investigated by 31P and 1H Magnetic Resonance Spectroscopy

• Suk EH
• Park PH
• Lim KH
• Lee JH
• Lim TH

• KMID: 1936360
• DOI: http://doi.org/10.4097/kjae.2000.38.2.340

Abstract

BACKGROUND: The effects of the inhibitor of nitric oxide synthase (NOS) in cerebral ischemia have been debated. Recently, it has been suggested that it depends on the amount of the inhibitor used. Therefore, this study was carried out to evaluate the effects of the NOS in the acute ischemia-reperfusion of the cat model using variable amounts of the inhibitor.
METHODS
Nineteen cats were divided into 3 groups: group 1 (n = 6), 10 mg/kg of N-nitro-L-arginine methyl ester (L-NAME); group 2 (n = 7), 0.5 mg/kg; group 3 (n = 6), control group. Incomplete global cerebral ischemia was induced by ligation of both carotid arteries with arterial hypotension (-40 mmHg) for 30 minutes followed by 3 hours of reperfusion. The NOS inhibitor (L-NAME), was injected intraperitoneally 5 minutes before reperfusion. 31P and 1H MR spectroscopy were performed. A series of spectra was acquired in the time intervals before ligation, during ischemia, and after reperfusion.
RESULTS
Phosphocreatine/inorganic phosphate (PCr/Pi) ratios for group 1 were significantly lower than for groups 2 and 3 (P < 0.05), and there was no significant difference between groups 2 and 3. Lactate/N-acetyl aspartate (Lac/NAA) and lactate/creatine (Lac/Cr) ratios at 180 minutes after reperfusion were higher for group 1 than for groups 2 and 3 (P < 0.05). There were no significant differences in pH and lactate/choline (Lac/Cho) ratios among the 3 groups.
CONCLUSIONS
It is demonstrated that the effect of the NOS inhibitor is dosage dependent. A high dose (10 mg/kg) of L-NAME seems to have an adverse effect on recovery of the ischemia, but a low dose (0.5 mg/kg) seems to have no effect.

Keyword

Brain: ischemia; Pharmacology: L-NAME; nitric oxide synthase inhibitor

MeSH Terms

Animals
Aspartic Acid
Brain Ischemia
Brain*
Carotid Arteries
Cats*
Energy Metabolism*
Hydrogen-Ion Concentration
Hypotension
Ischemia
Ligation
Magnetic Resonance Spectroscopy*
NG-Nitroarginine Methyl Ester
Nitric Oxide Synthase*
Nitric Oxide*
Reperfusion
Aspartic Acid
NG-Nitroarginine Methyl Ester
Nitric Oxide
Nitric Oxide Synthase