Figure 3. BzATP induces a transmembrane Ca²⁺ influx.

A, the white outline in the upper panel shows a paranodal Schwann cell region within an isolated rat spinal root stained with the Ca²⁺-sensitive dyes Calcium Green-1 and Fura Red. Changes in [Ca²⁺]_i were measured during application of BzATP (150 μM) into the standard and into a Ca²⁺-free bathing solution. B, a similar experimental protocol was applied to a different rat spinal root. In this case, changes in [Ca²⁺]_i were measured during application of UTP (300 μM) into the standard and into a Ca²⁺-free bathing solution. Note that only the BzATP-induced intracellular Ca²⁺ transient was completely and reversibly blocked during removal of extracellular Ca²⁺.