Figure 4.

Effect of Ca²⁺-removal, Ni²⁺ and amlodipine, on responses to angiotensin II, NE and KPSS. (A) Traces showing the effect of a Ca²⁺ free solution (PSS₀Ca) on contraction (upper trace) and [Ca²⁺]_i in the same vessel in response to angiotensin II (100 nM). Exposure to drugs is indicated by the bar, and time of washout (w/o) is also shown. (B) Comparison of peak increase in [Ca²⁺]_i (Δ[Ca²⁺]_i) in response to angiotensin II following no treatment, Ni²⁺ (2 mM; n=4), amlodipine (10 μM; n=3) or Ca²⁺-free PSS (PSS₀Ca; n=4). Right panel shows effect of amlodipine (10 μM; n=3) on peak increase in [Ca²⁺]_i induced by KPSS. Bars represent mean±s.e.mean of per cent peak control response. ^*Indicates P<0.05. (C) Comparison of peak increase in force in response to angiotensin II following no treatment, Ni²⁺ (2 mM; n=4), amlodipine (10 μM; n=3) or Ca²⁺-free PSS (PSS₀Ca; n=4). Right panel shows effect of amlodipine (10 μM; n=3) on peak increase in force induced by KPSS. Bars represent mean±s.e.mean of per cent peak control response. ^*Indicates P<0.05.