Identification of P2Y receptor subtypes in human muller glial cells by physiology, single cell RT-PCR, and immunohistochemistry.
OBJECTIVE
Retinal Müller glial cells are known to express metabotropic P2Y receptors. The present study was conducted to identify certain subtypes of P2Y receptors in human Müller cells.


METHODS
The patch-clamp technique was used to measure increases of Ca(2+)-dependent K+ currents mediated by the activation of P2Y receptors in freshly isolated human Müller cells. Several P2 agonists were used. Subsequently, the cells were harvested into the patch pipette and a single cell RT-PCR was performed. Moreover, retinal tissue from organ donors was used for immunohistochemistry.


RESULTS
The electrophysiological data were consistent with the expression of P2Y1, P2Y2, P2Y4, and P2Y6 receptor subtypes. RT-PCR revealed that mRNA for all these subtypes was present in Müller cells. However, the incidence of P2Y2 receptor mRNA was significantly lower than that of the other subtypes. Immunoreactivity for all four subtypes was found in retinal tissue, partly colocalized with immunoreactivity for vimentin.


CONCLUSIONS
The presented data obtained by different techniques revealed that human Müller cells express P2Y1, P2Y2, P2Y4, and P2Y6 receptors. The specific roles of these receptor subtypes in retinal physiology and/or pathophysiology remain to be investigated in future studies.
Fries
Julia E
JE
Forschungsstelle für Experimentelle Ophthalmologie, Universitätsaugenklinik, Universität Tübingen, Tübingen, Germany.
Goczalik
Iwona M
IM
Wheeler-Schilling
Thomas H
TH
Kohler
Konrad
K
Guenther
Elke
E
Wolf
Sebastian
S
Wiedemann
Peter
P
Bringmann
Andreas
A
Reichenbach
Andreas
A
Francke
Mike
M
Pannicke
Thomas
T
D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D009457:Neuroglia / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D024681:Potassium Channels, Calcium-Activated / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D018048:Receptors, Purinergic P2 / Q000235:genetics / Q000378:metabolism*; D058472:Receptors, Purinergic P2Y1; D058473:Receptors, Purinergic P2Y2; D012160:Retina / Q000166:cytology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018630:Vitreoretinopathy, Proliferative / Q000601:surgery
C546382:P2RY1 protein, human; C546385:P2RY2 protein, human; D024681:Potassium Channels, Calcium-Activated; D012333:RNA, Messenger; D018048:Receptors, Purinergic P2; D058472:Receptors, Purinergic P2Y1; D058473:Receptors, Purinergic P2Y2; C104749:purinoceptor P2Y4; C099845:purinoceptor P2Y6