Figure 10.

Effects of 100 μM Ni²⁺ on contraction amplitude and frequency over the entire pressure range for popliteal lymphatics from WT and Ca_v3.1^−/−; Ca_v3.2^−/− double KO mice. (A) Example recordings from a WT popliteal lymphatic before and after addition of 100 μM Ni²⁺ to the bath. (B) Summary data for spontaneous contraction amplitude and frequency from eight WT vessels. 100 μM Ni²⁺ reduced amplitude by 40–50% at pressures < 3 cmH₂O and by 20–30% at higher pressures. Ni²⁺ caused an increase in frequency at all pressures, with a more pronounced effect at lower pressures. (C) Example recordings from a Ca_v3.1^−/−; Ca_v3.2^−/− double KO mouse before and after addition of 100 μM Ni²⁺ to the bath. Summary data for amplitude and frequency at each pressure are shown in D for nine Ca_v3.1^−/−; Ca_v3.2^−/− vessels. Ni²⁺ led to 20–30% reduction in amplitude at all pressures and an increase in frequency at all pressures except 0.5 cmH₂O. At the two lowest pressures contraction amplitude was highly variable over time, with small contractions interspersed with intermediate and large-amplitude contractions. For this analysis we did not count contractions less than 5 μm in amplitude at pressures ≤ 3 cmH₂O because they were non-propulsive and usually not highly entrained. Counting these contractions would have led to even higher determinations of frequency at those pressures.