Abstract
Experiments were performed to determine whether L-arginine transport regulates nitric oxide (NO) production and hemodynamics in the renal medulla. The effects of renal medullary interstitial infusion of cationic amino acids, which compete with L-arginine for cellular uptake, on NO levels and blood flow in the medulla were examined in anesthetized rats. NO concentration in the renal inner medulla, measured with a microdialysis-oxyhemoglobin trapping technique, was significantly decreased by 26-44% and renal medullary blood flow, measured by laser Doppler flowmetry, was significantly reduced by 20-24% during the acute renal medullary interstitial infusion of L-ornithine, L-lysine, and L-homoarginine (1 μmol·kg-1·min-1 each; n = 6-8/group). In contrast, intramedullary infusion of L-arginine increased NO concentration and medullary blood flow. Flow cytometry experiments with 4-amino-5-methylamino-2′,7′-difluorescein diacetate, a fluorophore reactive to intracellular NO, demonstrated that L-ornithine, L-lysine, and L-homoarginine decreased NO by 54-57% of control, whereas L-arginine increased NO by 21% in freshly isolated inner medullary cells (1 mmol/l each, n > 1,000 cells/experiment). The mRNA for the cationic amino acid transporter-1 was predominantly expressed in the inner medulla, and cationic amino acid transporter-1 protein was localized by immunohistochemistry to the collecting ducts and vasa recta in the inner medulla. These results suggest that L-arginine transport by cationic amino acid transport mechanisms is important in the production of NO and maintenance of blood flow in the renal medulla.
| Original language | English (US) |
|---|---|
| Pages (from-to) | R1478-R1485 |
| Journal | American Journal of Physiology - Regulatory Integrative and Comparative Physiology |
| Volume | 287 |
| Issue number | 6 56-6 |
| DOIs | |
| State | Published - Dec 1 2004 |
| Externally published | Yes |
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Keywords
- Cytometry
- Kidney
- Laser Doppler flowmetry
- Microdialysis
ASJC Scopus subject areas
- Physiology
- Physiology (medical)
Cite this
L-Arginine uptake affects nitric oxide production and blood flow in the renal medulla. / Kakoki, Masao; Kim, Hyung Suk; Arendshorst, William J.; Mattson, David L.
In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 287, No. 6 56-6, 01.12.2004, p. R1478-R1485.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - L-Arginine uptake affects nitric oxide production and blood flow in the renal medulla
AU - Kakoki, Masao
AU - Kim, Hyung Suk
AU - Arendshorst, William J.
AU - Mattson, David L.
PY - 2004/12/1
Y1 - 2004/12/1
N2 - Experiments were performed to determine whether L-arginine transport regulates nitric oxide (NO) production and hemodynamics in the renal medulla. The effects of renal medullary interstitial infusion of cationic amino acids, which compete with L-arginine for cellular uptake, on NO levels and blood flow in the medulla were examined in anesthetized rats. NO concentration in the renal inner medulla, measured with a microdialysis-oxyhemoglobin trapping technique, was significantly decreased by 26-44% and renal medullary blood flow, measured by laser Doppler flowmetry, was significantly reduced by 20-24% during the acute renal medullary interstitial infusion of L-ornithine, L-lysine, and L-homoarginine (1 μmol·kg-1·min-1 each; n = 6-8/group). In contrast, intramedullary infusion of L-arginine increased NO concentration and medullary blood flow. Flow cytometry experiments with 4-amino-5-methylamino-2′,7′-difluorescein diacetate, a fluorophore reactive to intracellular NO, demonstrated that L-ornithine, L-lysine, and L-homoarginine decreased NO by 54-57% of control, whereas L-arginine increased NO by 21% in freshly isolated inner medullary cells (1 mmol/l each, n > 1,000 cells/experiment). The mRNA for the cationic amino acid transporter-1 was predominantly expressed in the inner medulla, and cationic amino acid transporter-1 protein was localized by immunohistochemistry to the collecting ducts and vasa recta in the inner medulla. These results suggest that L-arginine transport by cationic amino acid transport mechanisms is important in the production of NO and maintenance of blood flow in the renal medulla.
AB - Experiments were performed to determine whether L-arginine transport regulates nitric oxide (NO) production and hemodynamics in the renal medulla. The effects of renal medullary interstitial infusion of cationic amino acids, which compete with L-arginine for cellular uptake, on NO levels and blood flow in the medulla were examined in anesthetized rats. NO concentration in the renal inner medulla, measured with a microdialysis-oxyhemoglobin trapping technique, was significantly decreased by 26-44% and renal medullary blood flow, measured by laser Doppler flowmetry, was significantly reduced by 20-24% during the acute renal medullary interstitial infusion of L-ornithine, L-lysine, and L-homoarginine (1 μmol·kg-1·min-1 each; n = 6-8/group). In contrast, intramedullary infusion of L-arginine increased NO concentration and medullary blood flow. Flow cytometry experiments with 4-amino-5-methylamino-2′,7′-difluorescein diacetate, a fluorophore reactive to intracellular NO, demonstrated that L-ornithine, L-lysine, and L-homoarginine decreased NO by 54-57% of control, whereas L-arginine increased NO by 21% in freshly isolated inner medullary cells (1 mmol/l each, n > 1,000 cells/experiment). The mRNA for the cationic amino acid transporter-1 was predominantly expressed in the inner medulla, and cationic amino acid transporter-1 protein was localized by immunohistochemistry to the collecting ducts and vasa recta in the inner medulla. These results suggest that L-arginine transport by cationic amino acid transport mechanisms is important in the production of NO and maintenance of blood flow in the renal medulla.
KW - Cytometry
KW - Kidney
KW - Laser Doppler flowmetry
KW - Microdialysis
UR - http://www.scopus.com/inward/record.url?scp=8844234900&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=8844234900&partnerID=8YFLogxK
U2 - 10.1152/ajpregu.00386.2004
DO - 10.1152/ajpregu.00386.2004
M3 - Article
C2 - 15319219
AN - SCOPUS:8844234900
VL - 287
SP - R1478-R1485
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
SN - 0363-6135
IS - 6 56-6
ER -