Figure 1.
Effects of noradrenaline, moxonidine, clonidine and PGE2 on electrically evoked tritium overflow from segments of the rat vena cava preincubated with [3H]-noradrenaline and interaction with agmatine, clonidine and/or rauwolscine. Interacting drugs were present from 13 min before S1 until the end of the experiments. The experiments with noradrenaline and the corresponding controls were carried out in the presence of 1 μM propranolol throughout superfusion. Ordinate, S3/S2, S4/S2 and S5/S2 overflow ratios, expressed as percentage of ratios in corresponding control experiments without noradrenaline, moxonidine, clonidine or PGE2. Means±s.e.mean from 5–12 tissue segments. All Sn/S2 ratios below 75% of the corresponding Sn/S2 ratios in the respective controls were significantly different from these control ratios (i.e. in the absence of the respective agonist).+P<0.05, compared with the effect of the corresponding agonist concentration in the absence of agmatine.