Figure 2.

The effect of Ba²⁺ and ouabain on ACh- and K⁺-induced dilatation. (a) In 10 pressurized arteries where high (10.58 mM) produced dilatation, 30 μM Ba²⁺ did not affect ACh-induced dilatations, but four out of 10 K⁺-induced dilatations were blocked. This shows a representative example where 30 μM Ba²⁺ blocked K⁺-induced dilatation. (b) Mean data for K⁺-induced dilatations blocked by 30 μM Ba²⁺ (n=4). (c) Mean data for K⁺-induced dilatations unaffected by 30 μM Ba²⁺ (n=6). (d) In pressurized arteries where high (10.58 mM) K⁺ failed to produce dilatation, 1 mM ouabain increased the level of tone, but had no significant effect on ACh-induced dilatation. Combined application of 30 μM Ba²⁺ and 1 mM ouabain significantly depressed ACh-induced dilatation. (e) Mean data from five similar experiments. ^*Shows significance (P<0.05) compared to control.