P2Y receptor-mediated stimulation of Müller glial DNA synthesis

PURPOSE: To determine whether activation of P2Y receptors may increase the DNA synthesis rate of cultured Müller cells and to investigate whether adenosine 5'-triphosphate (ATP)-induced Müller cell proliferation is mediated by an intracellular calcium increase.

METHODS: Primary cultures of Müller cells of the guinea pig were treated with test substances for 16 hours. The DNA synthesis rate was assessed by a bromodeoxyuridine immunoassay, and ATP-induced elevations of the intracellular calcium concentration were recorded by fura-2 imaging.

RESULTS: ATP or uridine triphosphate (UTP) increased the DNA synthesis rate whereas alpha,beta-methylene-ATP, 2-methyl-thio-ATP, and adenosine were ineffective, indicating that the action of ATP was through P2Y receptors. The effect of ATP was dose dependent, with an EC(50) of 5.9 microM. The mitogenic effect of ATP required an elevation of the intracellular calcium and a calcium influx into Müller cells. Blockers of calcium-permeable channels (nickel ions) or of calcium-dependent potassium (BK) channels (iberiotoxin, charybdotoxin) inhibited the ATP-stimulated DNA synthesis. In calcium-imaging experiments, ATP-evoked intracellular calcium transients were significantly shortened in the presence of extracellular nickel ions or of iberiotoxin. A correlation was found between the duration of the ATP-evoked calcium transients and the basal proliferation rate of the cultures.

CONCLUSIONS: The results indicate that the ATP-induced elevation of Müller glial DNA synthesis is dependent on an influx of calcium ions from the extracellular space and that the inhibiting effect of BK channel blockers on ATP-evoked DNA synthesis is caused by an inhibition of this influx. The amount of the calcium influx seems to be directly correlated to the strength of the ATP-evoked proliferation.

Medienart:

Artikel

Erscheinungsjahr:

2002

Erschienen:

2002

Enthalten in:

Zur Gesamtaufnahme - volume:43

Enthalten in:

Investigative ophthalmology & visual science - 43(2002), 3 vom: 01. März, Seite 766-73

Sprache:

Englisch

Beteiligte Personen:

Moll, Vanessa [VerfasserIn]
Weick, Michael [VerfasserIn]
Milenkovic, Ivan [VerfasserIn]
Kodal, Hannes [VerfasserIn]
Reichenbach, Andreas [VerfasserIn]
Bringmann, Andreas [VerfasserIn]

Themen:

8L70Q75FXE
9007-49-2
Adenosine Triphosphate
Calcium
Calcium Channel Blockers
Calcium Channels
DNA
Fura-2
Journal Article
Receptors, Purinergic P2
Research Support, Non-U.S. Gov't
SY7Q814VUP
TSN3DL106G
UT0S826Z60
Uridine Triphosphate

Anmerkungen:

Date Completed 28.03.2002

Date Revised 19.11.2015

published: Print

Citation Status MEDLINE

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM117528005