Figure 4
From: ATP signaling in the integrative neural center of Aplysia californica
Pharmacology of AcP2X receptors in Xenopus oocytes. (A) Example of currents induced by 250 μM ATP. ATP was applied to oocytes for 15 s, in the presence of varying concentrations of suramin (HP = − 70 mV). (B) Mean responses to 250 μM ATP in the presence of 1–250 μM suramin. There was a suramin-resistant component of the AcP2X current. Symbols represent mean ± S.E n = 7, oocytes). (C) Traces recorded in response to 250 μM ATP in the presence of varying concentrations of the second antagonist, PPADS (concentrations are shown in μM, and all applications are indicated by the solid lines) (n = 7, oocytes). (D) Mean responses to 250 μM of ATP in the presence of the PPADS (a fast component of responses—closed squares, slow component—triangles). PPADS was an effective antagonist in the range of 1–250 μM. Fitting of the data using the sigmoidal dose–response curve by a continuous line, IC50fast = 211.2. Symbols represent the mean ± S.E (n = 7, oocytes). (E) The suramin proved to be a more effective blocker of the ATP-activated channels among the two antagonists tested. A chart of mean currents (% of 250 µM ATP response) in the presence of 250 µM Suramin and 250 µM PPADS. Mean currents were normalized to the response given by 250 μM of ATP. Symbols represent mean ± S.E; statistically significant differences (Student’s t-test) from control (P < 0.05) are indicated by asterisks (***) above the bars (n = 7, oocytes).
