Main subunits of ionotropic glutamate receptors are expressed in isolated rat brain microvessels.
Excitatory amino acids are known to modulate blood-brain barrier (BBB) permeability, however, the information on glutamate receptors in cerebral capillaries is inconsistent. In the present study, freshly isolated microvessels obtained from saline-perfused rat brains were used. Gene expression of the main N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid (AMPA) receptor subunits NMDAR1 and GLUR1, respectively, were investigated by reverse transcription-polymerase chain reaction (RT-PCR). The results confirmed the presence of both NMDAR1 and GLUR1 mRNAs in microvessels of seven brain regions studied. Moreover, specific binding of [3H]glutamate to capillary membranes and its displacement by AMPA, NMDA and metabotropic, but not kainate receptor agonists were observed. These results suggest that rat brain capillaries and/or albuminally adhering astrocyte processes possess functional glutamate receptors. Thus, the effects of glutamate agonists and antagonists in modulation of BBB function might be mediated directly by cerebral microvessels.
St'astný
Frantisek
F
Institute of Physiology, Academy of Sciences of the Czech Republic, Prague.
Schwendt
Marek
M
Lisý
Václav
V
Jezová
Daniela
D
D000818:Animals; D001812:Blood-Brain Barrier / Q000502:physiology*; D001921:Brain / Q000098:blood supply* / Q000378:metabolism*; D015870:Gene Expression / Q000502:physiology*; D018698:Glutamic Acid / Q000378:metabolism*; D008297:Male; D008833:Microcirculation / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D018091:Receptors, AMPA / Q000235:genetics*; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics*
D018698:Glutamic Acid; D012333:RNA, Messenger; D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate