We used a single cell calcium

We used a single cell calcium those imaging approach, loading hippocampal cultured neurons with the selective ratiometric calcium dye, Fura 2. We found that 100 umol l glutamate caused an immediate rise in intracel lular free calcium concentration as gauged by an increase in the Fura 2 fluorescence ratio of 0. 38 0. 03 above the control. The presence of 100 ng ml IL 1B consistently increased this effect of glutamate, whereas IL 1B alone failed to trigger any modification in the Fura 2 signal. Pre incubation of cells with 50 nmol l SCH58261 attenu ated this effect of IL 1B on the glutamate induced increase of i. By con trast, SCH58261 actually tended to amplify the effect of glu tamate alone, whereas SCH58261 alone had no effect on i.

Apart from this initial effect of glutamate on calcium transients, we also evaluated how IL 1B and A2AR blockade affected the ability of neurons to adapt to the continuous presence of glutamate. Thus, we evaluated the variation of the Fura 2 fluorescence ratio from its peak value shortly after the addition of Inhibitors,Modulators,Libraries glutamate until the end of the incuba tion period with glutamate. Most neurons were able to adapt to the continuous Inhibitors,Modulators,Libraries presence of glutamate and decrease their i over time. By contrast, in the presence of 100 ng ml IL 1B, neurons lost their capacity to adapt to the continuous presence of glutamate, as testified by their tendency Inhibitors,Modulators,Libraries to continue increasing their i. Notably, blockade of A2AR with SCH58261 inverted this effect of IL 1B. Again, SCH58261 selectively pre vented the exacerbation by IL 1B of glutamate induced responses, and in fact, SCH58261 actually enhanced the re sponse to glutamate Inhibitors,Modulators,Libraries alone.

This apparently contra dictory ability of SCH58261 to increase slightly the glutamate induced intracellular calcium dynamics and to abrogate the exacerbating effect of IL 1B on Inhibitors,Modulators,Libraries glutamate induced effects probably results from the pleiotropic nature of A2AR mediated signaling and its plasticity under different experimental conditions. As a final attempt to link calcium deregulation upon ex posure to glutamate and IL 1B with the A2AR mediated control of the exacerbation by IL 1B of glutamate induced neurotoxicity, we tested whether inhibition of either p38 or JNK might also prevent the exacerbation by IL 1B of the glutamate induced dynamics of intracellular calcium in cul tured neurons. thoroughly The p38 inhibitor SB203580, attenuated the exacerbation by IL 1B of glutamate induced initial calcium entry and prevented the calcium deregulation. The JNK inhibitor SP600125 also attenuated the effect of IL 1B with glutam ate, although this was not significant, and neither of these inhibitors alone displayed any evident effects.

Leave a Reply

Your email address will not be published. Required fields are marked *

*

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>