Deficits in Endogenous Adenosine Formation by Ecto-5′-Nucleotidase/CD73 Impair Neuromuscular Transmission and Immune Competence in Experimental Autoimmune Myasthenia Gravis

Figure 4

Tonic activation of R is significantly impaired at motor endplates of myasthenic rats. (a) Confocal micrographs showing immunoreactivity against R (green) on motor endplates from rat hemidiaphragms labeled with TMR--BTX (red) from naïve, control, and EAMG rats. Scale bar: 10 m. Two distinct R antibodies, AlphaDiagnostics (A2aR21-P) and Chemicon (05-717, Clone 7F6-G5-A2), were used was indicated. (b) Time course of tritium outflow from phrenic nerve terminals from control and EAMG animals taken from typical experiments in the absence (no drug, open circles) and in the presence of the selective R antagonist, ZM241285 (50 nM) (filled triangles). [³H]-ACh release was elicited by stimulating the phrenic nerve trunk with 750 pulses delivered with a frequency of 5 Hz at the indicated times ( and ). ZM241285 (50 nM) was applied 15 min before . (c) Modification of the ratio caused by ZM241285 (50 nM) in naïve, control, and EAMG rats. Each column represents pooled data from five (naïve and control) and seven (EAMG) animals. The vertical bars represent mean SEM. (one-way ANOVA followed by Dunnett’s modified -test) when compared to naïve and control (CFA) rats.

(a)

(b)

(c)