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Functional expression of the organic cation/carnitine transporter 2 in rat astrocytes.
J Neurochem. 2006 Apr; 97(2):424-34.JN

Abstract

In this study, we sought to identify the transporters that mediate the uptake of L-carnitine and acetyl-L-carnitine in cultured rat cortical astrocytes. L-[(3)H]carnitine and acetyl-L-[(3)H]carnitine uptake were both saturable, and mediated by a single Na(+)-dependent transport system. Uptake of both was inhibited by L-carnitine, D-carnitine, acetyl-L-carnitine and various organic cations. Acylcarnitines (acetyl-, butyryl-, hexanoyl-, octanoyl- and palmitoyl-L-carnitine) also interacted with L-[(3)H]carnitine and acetyl-L-[(3)H]carnitine transport. 2-Amino-2-norbornane carboxylic acid, a known inhibitor of amino acid transporter B(0,+) (ATB(0,+)), did not cause any significant inhibition. A highly significant correlation was found between the potencies of acylcarnitines in the inhibition of L-[(3)H]carnitine and acetyl-L-[(3)H]carnitine uptake and the acyl chain length of acylcarnitines. The expression of mRNA for organic cation/carnitine transporters (OCTNs), carnitine transporter 2 (CT2) and ATB(0,+) in astrocytes was investigated by reverse transcription (RT)-PCR. OCTN2 mRNA was expressed in astrocytes, whereas the expression of OCTN1, OCTN3 and CT2 mRNA could not be detected. ATB(0,+) mRNA was expressed at very low levels in astrocytes. Western blotting analysis indicated that anti-OCTN2 polyclonal antibody recognized a band of 70 kDa in both kidney and astrocyte preparations. OCTN2 immunoreactivity was detected in rat astrocytes by immunocytochemical staining. Inhibition of OCTN2 expression by RNA interference significantly inhibited L-[(3)H]carnitine and acetyl-L-[(3)H]carnitine uptake into astrocytes. These results suggest that OCTN2 is functionally expressed in rat astrocytes, and is responsible for L-carnitine and acetyl-L-carnitine uptake in these cells.

Authors+Show Affiliations

Department of Pharmacology, Tokyo Medical University, Japan.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16539668

Citation

Inazu, Masato, et al. "Functional Expression of the Organic Cation/carnitine Transporter 2 in Rat Astrocytes." Journal of Neurochemistry, vol. 97, no. 2, 2006, pp. 424-34.
Inazu M, Takeda H, Maehara K, et al. Functional expression of the organic cation/carnitine transporter 2 in rat astrocytes. J Neurochem. 2006;97(2):424-34.
Inazu, M., Takeda, H., Maehara, K., Miyashita, K., Tomoda, A., & Matsumiya, T. (2006). Functional expression of the organic cation/carnitine transporter 2 in rat astrocytes. Journal of Neurochemistry, 97(2), 424-34.
Inazu M, et al. Functional Expression of the Organic Cation/carnitine Transporter 2 in Rat Astrocytes. J Neurochem. 2006;97(2):424-34. PubMed PMID: 16539668.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Functional expression of the organic cation/carnitine transporter 2 in rat astrocytes. AU - Inazu,Masato, AU - Takeda,Hiroshi, AU - Maehara,Katsuyuki, AU - Miyashita,Kyoji, AU - Tomoda,Akio, AU - Matsumiya,Teruhiko, Y1 - 2006/03/15/ PY - 2006/3/17/pubmed PY - 2006/6/9/medline PY - 2006/3/17/entrez SP - 424 EP - 34 JF - Journal of neurochemistry JO - J Neurochem VL - 97 IS - 2 N2 - In this study, we sought to identify the transporters that mediate the uptake of L-carnitine and acetyl-L-carnitine in cultured rat cortical astrocytes. L-[(3)H]carnitine and acetyl-L-[(3)H]carnitine uptake were both saturable, and mediated by a single Na(+)-dependent transport system. Uptake of both was inhibited by L-carnitine, D-carnitine, acetyl-L-carnitine and various organic cations. Acylcarnitines (acetyl-, butyryl-, hexanoyl-, octanoyl- and palmitoyl-L-carnitine) also interacted with L-[(3)H]carnitine and acetyl-L-[(3)H]carnitine transport. 2-Amino-2-norbornane carboxylic acid, a known inhibitor of amino acid transporter B(0,+) (ATB(0,+)), did not cause any significant inhibition. A highly significant correlation was found between the potencies of acylcarnitines in the inhibition of L-[(3)H]carnitine and acetyl-L-[(3)H]carnitine uptake and the acyl chain length of acylcarnitines. The expression of mRNA for organic cation/carnitine transporters (OCTNs), carnitine transporter 2 (CT2) and ATB(0,+) in astrocytes was investigated by reverse transcription (RT)-PCR. OCTN2 mRNA was expressed in astrocytes, whereas the expression of OCTN1, OCTN3 and CT2 mRNA could not be detected. ATB(0,+) mRNA was expressed at very low levels in astrocytes. Western blotting analysis indicated that anti-OCTN2 polyclonal antibody recognized a band of 70 kDa in both kidney and astrocyte preparations. OCTN2 immunoreactivity was detected in rat astrocytes by immunocytochemical staining. Inhibition of OCTN2 expression by RNA interference significantly inhibited L-[(3)H]carnitine and acetyl-L-[(3)H]carnitine uptake into astrocytes. These results suggest that OCTN2 is functionally expressed in rat astrocytes, and is responsible for L-carnitine and acetyl-L-carnitine uptake in these cells. SN - 0022-3042 UR - https://www.unboundmedicine.com/medline/citation/16539668/Functional_expression_of_the_organic_cation/carnitine_transporter_2_in_rat_astrocytes_ L2 - https://doi.org/10.1111/j.1471-4159.2006.03757.x DB - PRIME DP - Unbound Medicine ER -