Distribution of monocarboxylate transporters MCT1 and MCT2 in rat retina

D. Z. Gerhart, R. L. Leino, L. R. Drewes

Research output: Contribution to journalArticle

82 Citations (Scopus)

Abstract

Transport of lactic acid and other monocarboxylates such as pyruvate and the ketone bodies through cellular membranes is facilitated by specific transport proteins. We used chicken polyclonal antibodies to the monocarboxylate transporters-1 and -2 to determine their cellular and subcellular distributions in rat retina, and we compared these distributions to those of the glucose transporters-1 and -3. Monocarboxylate transporter-1 was most highly expressed by the apical processes of retinal pigment epithelium that surround the outer segments of the photoreceptor cells. In contrast to glucose transporter-1, monocarboxylate transporter-1 was not detected on the basal membranes of pigment epithelium. The luminal and abluminal endothelial plasma membranes in retina also exhibited heavy labeling by antibody to monocarboxylate transporter-1. In addition, this transporter was associated with the Muller cell microvilli, the plasma membranes of the rod inner segments, and all retinal layers between the inner and external limiting membranes. Monocarboxylate transporter-2 was found to be abundantly expressed on the inner (basal) plasma membrane of Muller cells and by glial cell processes surrounding retinal microvessels. This transporter was also present in the plexiform and nuclear layers but was not detected beyond the external limiting membrane. Recent studies have shown that lactic acid transport is of particular importance at endothelial and epithelial barriers where membranes of adjoining cells are linked by tight junctions. Our results suggest that monocarboxylate transporter-1 functions to transport lactate between the retina and the blood, both at the retinal endothelium and the pigment epithelium. The location of monocarboxylate transporter-2 on glial foot processes surrounding retinal vessels suggests that this transporter is also important in blood-retinal lactate exchange. In addition, the abundance of these transporters in Muller cells and synaptic (plexiform) layers suggests that they function in lactate exchange between neurons and glia, supporting the notion that lactate plays a key role in neural metabolism.

Original languageEnglish (US)
Pages (from-to)367-375
Number of pages9
JournalNeuroscience
Volume92
Issue number1
DOIs
StatePublished - Aug 1 1999

Fingerprint

Retina
Lactic Acid
Ependymoglial Cells
Cell Membrane
Neuroglia
Membranes
Facilitative Glucose Transport Proteins
Retinal Pigment Epithelium
Retinal Photoreceptor Cell Inner Segment
Retinal Vessels
Ketone Bodies
Photoreceptor Cells
Antibodies
Tight Junctions
Microvilli
Microvessels
Pyruvic Acid
Endothelium
Foot
Chickens

Keywords

  • Blood-ocular barrier
  • Glucose
  • Lactate
  • Monocarboxylates
  • Retina
  • Transporters

Cite this

Distribution of monocarboxylate transporters MCT1 and MCT2 in rat retina. / Gerhart, D. Z.; Leino, R. L.; Drewes, L. R.

In: Neuroscience, Vol. 92, No. 1, 01.08.1999, p. 367-375.

Research output: Contribution to journalArticle

Gerhart, D. Z. ; Leino, R. L. ; Drewes, L. R. / Distribution of monocarboxylate transporters MCT1 and MCT2 in rat retina. In: Neuroscience. 1999 ; Vol. 92, No. 1. pp. 367-375.
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