Figure 6.

Effect of L-citrulline (470 μM) on the resting outflow of (a) adenosine and (b) ATP (and related adenine nucleotides) from the rat innervated hemidiaphragm in the absence and in the presence of the nucleoside transport inhibitor, NBTI (10 μM). L-citrulline (470 μM) was applied 15 min before S₂; NBTI (10 μM) was present throughout the assay, including S₁ and S₂. The ordinates represent the resting outflow of (a) adenosine and (b) ATP (and related adenine nucleotides) expressed by the B_2−n/B_1−n ratios; B_1−n and B_2−n correspond to the adenosine or adenine nucleotide content in bath samples collected n minutes before the first (without L-citrulline) and the second (in the presence of L-citrulline) stimulation periods, respectively. Each column represents pooled data from four experiments. The vertical bars represent s.e.m. ^*P<0.05 (one-way ANOVA followed by Dunnett's modified t-test), significant differences from the control.