Protein Information

ID 306
Name NMDA receptors (protein family or complex)
Synonyms Glutamate [NMDA] receptor; Glutamate [NMDA] receptors; N methyl D aspartate receptor; N methyl D aspartate receptors; NMDA receptor; NMDA receptors

Compound Information

ID 333
Name chloralose
CAS

Reference

PubMed Abstract RScore(About this table)
7740580 Meng W, Tobin JR, Busija DW: Glutamate-induced cerebral vasodilation is mediated by nitric oxide through N-methyl-D-aspartate receptors. Stroke. 1995 May;26(5):857-62; discussion 863.
BACKGROUND AND PURPOSE: It was found that glutamate, a major neurotransmitter, is vasoactive in the cerebral circulation. However, the mechanism is unclear. This study was designed to investigate the role of nitric oxide (NO) and N-methyl-D-aspartate (NMDA) receptors in cerebral arteriolar dilation to glutamate. METHODS: Newborn, chloralose-anesthetized pigs were equipped with a closed cranial window. The diameter of pial arterioles was measured by means of intravital microscopy, and NO synthase (NOS) activity in brain cortex was determined by the conversion assay of [14C] arginine to [14C] citrulline. RESULTS: Topical application of glutamate at 10 (-7), 10 (-6), and 10 (-5) mol/L (n = 5) increased the mean diameter by 12 +/- 3%, 13 +/- 2%, and 18 +/- 3% (+/- SEM), respectively (baseline, 91 +/- 10 microns; P < .05). Similarly, NMDA application at the above doses (n = 5) dilated arterioles by 10 +/- 2%, 16 +/- 3%, and 18 +/- 6%, respectively (baseline, 97 +/- 4 microns; P < .05). Topical application of 10 (-4) mol/L NG-nitro-L-arginine (L-NNA), which inhibited NOS activity by 93%, blocked the arteriolar dilation to glutamate or NMDA. Furthermore, administration of MK-801, a potent inhibitor of NMDA receptors, blocked glutamate-induced vasodilation completely in both topical application (10 (-5) mol/L; n = 6) and intravenous administration (5 to 10 mg/kg; n = 5). In addition, neither L-NNA nor MK-801 attenuated the vasodilation to hypercapnia (PCO2 = 40 to 68 mm Hg). CONCLUSIONS: Glutamate-induced cerebral arteriolar dilation is mediated by NO through NMDA receptors, and NO does not play a major role in the cerebral arteriolar dilation to hypercapnia (PCO2 = 40 to 68 mm Hg) in newborn pigs.
3(0,0,0,3)