L-arginine decreases infarct size caused by middle cerebral arterial occlusion in SHR.
L-Arginine, but not D-arginine, serves as a precursor for the synthesis of nitric oxide (NO), a potent dilator of cerebral blood vessels. We examined the effects of administering L-arginine (300 mg/kg ip) on the volume of infarction in two models of focal cerebral ischemia in spontaneously hypertensive rats (SHR). L-Arginine was administered before (16 and 3 h) and after (5 min and 2 h) vessel occlusion, and animals were killed 24 h later. L-Arginine treatment decreased infarct size in rats subjected to distal middle cerebral arterial (MCA) plus ipsilateral common carotid arterial (CCA) occlusion by 31% [147 +/- 12 (saline) vs. 101 +/- 9 mm3 (L-arginine), P < 0.05]. D-Arginine, administered according to the same dosage and protocol, was without effect. In the group subjected to proximal MCA occlusion, L-arginine decreased infarction size in the striatum by 28% [47 +/- 5 (saline) vs. 34 +/- 3 mm3 (L-arginine), P < 0.05] and neocortex by 11% [193 +/- 7 (saline) vs. 171 +/- 8 mm3 (L-arginine), P < 0.05]. Changes in blood pressure or other measured physiological parameters did not account for the observed differences. The possible use of L-arginine for the treatment of focal cerebral ischemia merits further investigation.
Morikawa
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E
Stroke Research Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston 02114.
Huang
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Z
Moskowitz
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MA
D000818:Animals; D001120:Arginine / Q000494:pharmacology* / Q000627:therapeutic use; D002545:Brain Ischemia / Q000150:complications*; D002544:Cerebral Infarction / Q000188:drug therapy / Q000209:etiology / Q000473:pathology*; D006973:Hypertension / Q000473:pathology; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D013237:Stereoisomerism; D014664:Vasodilation / Q000187:drug effects*
D001120:Arginine