QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

Help viewing high resolution images Return to article

Fig. 4. Functional P2X7 receptors are restricted to the distal region of the axon and growth cones. (A) Hippocampal neurons cultured for 3 DIV were stained with antibodies against tyrosinated -tubulin and P2X7. Higher-magnification views of the boxed areas show the distal region of the axon stained for tyrosinated -tubulin or P2X7 receptor. Scale bar: 50 µm. (B) Distal region of an axon stained with anti--tubulin and anti-P2X7 antibodies. Note that -tubulin staining, unlike that of tyrosinated -tubulin, does not display an increasing distal gradient. (C,D) Graphs represent the fluorescence intensity of tubulin (red) and P2X7 (green) along the axon in the neurons shown in A (C) and B (D), quantified using the ImageJ program. (E) Images of the most distal region of the axon and the growth cone of hippocampal neurons stained with anti-tyrosinated--tubulin and anti-P2X7 antibodies. Note the absence of P2X7 staining in axons running parallel to a P2X7-positive distal region of an axon, where P2X7 is located in the microtubule domain of the axon and in the actin-rich domain (inset). (F,G) Images show hippocampal neurons loaded with Fura-2 dye. Insert in G shows a fluorescence image of a whole hippocampal neuron loaded with Fura-2. Different areas along the axon were analyzed (numbers in G and F). (H,I) Time course of the changes in Fura-2 fluorescence recorded in the axonal areas selected in F and G. The graph represents the ratio of the Fura-2 intensity at the 340 (F₃₄₀) and 380 (F₃₈₀) wavelengths. (H) Increase in intracellular Ca²⁺ induced by 1 mM ATP in the presence or absence of extracellular Mg²⁺ ions. Note that Ca²⁺ influx induced by ATP is higher in the absence of extracellular Mg²⁺. (I) Intracellular Ca²⁺ influx induced by 1 mM ATP was abolished when neurons were pre-incubated with BBG (1 µM) in the absence of extracellular Mg²⁺. The solid bars indicate the periods of stimulation; a KCl pulse (60 mM) was also applied to test the viability of the neurons.

Return to article