Basal tritium outflow (b1), electrically evoked tritium overflow (S1) and S2/S1 ratios from mesenteric and tail arteries.

Tissue preparations of mesenteric and caudal arteries were pre-incubated with [3H]-noradrenaline for 40 min. After pre-incubation with [3H]-noradrenaline, tissues were superfused with [3H]-noradrenaline free medium containing desipramine (400 nM). Tissues were stimulated twice at 30-min intervals (S1-S2; 100 pulses, 5 Hz, 1 ms, 50 mA): b1 refers to the 5-min period immediately before S1. The electrically-evoked tritium overflow was calculated by subtracting the estimated basal outflow from total outflow observed during and in the 25-min period subsequent to S1 and expressed as a percentage of the tissue tritium content at the onset of stimulation. Values presented are means±SEM and n denotes the number of tissue preparations. Means were compared for significance using one-way ANOVA, followed by post-hoc Holm-Sidak´s multicomparisons t-test. Significant differences from the respective solvent: *PBasal tritium outflow (b1), electrically evoked tritium overflow (S1) and S2/S1 ratios from mesenteric and tail arteries.