Purinergic activation of both spermatogonia and Sertoli cells in acute seminiferous cord sections. (A and B) Representative photomicrographs (merged IR-DIC and fluorescence images) illustrating the acute seminiferous cord slice preparation and experimental approach. (A) Overview of an exemplary section (200 µm) through agarose-embedded mouse seminiferous cords. Image shows typical experimental configurations of patch electrode (pipette; dotted lines) and perfusion pencil. Boxed area is shown at higher magnification in B. Whole-cell configuration and cell morphology are monitored by diffusion loading with a fluorophore (red). (C) Original whole-cell voltage-clamp recordings from a putative Sertoli cell (V_hold = −40 mV; S₁, S₅). Both low (10 µM; 5 s; top) and high (1 mM; 20 s; bottom) ATP concentrations induce gradually developing nondesensitizing inward currents. (D) Exemplary photomicrograph depicting a transverse section through a seminiferous cord (overlay of IR-DIC and fluorescence). A putative spermatogonium, diffusion loaded with fluorophore during whole-cell recording, is targeted by the patch pipette. (E) Original voltage-clamp recordings from a putative spermatogonium (V_hold = −40 mV; S₁, S₅) challenged with low (10 µM; 5 s; top) and high (1 mM; 20 s; bottom) ATP concentrations. (F) Quantitative analysis of current recordings from putative spermatogonia. Bar charts (means ± SEM) compare response parameters as a function of stimulus concentration (10 µM vs. 1 mM ATP). Diagrams depict peak current amplitudes (left), desensitization rate during prolonged stimulation (middle), and peak current desensitization according to a double-pulse stimulation paradigm (5 s; ISI = 60–240 s; right). Numbers of cells as shown above bars. Asterisks (*) indicate statistical significance, P ≤ 0.01 (paired t tests).