Figure 1.
The effects of lolitrem B and paxilline on blood pressure and heart rate in Kcnma1−/− mice and wild-type littermates.
Inhibitors were added immediately after the control reading at time zero as indicated by the arrow. Mean blood pressure following treatment with (A) 4 mg/kg lolitrem B, or (B) 8 mg/kg paxilline. Heart rate following treatment with (C) lolitrem B, or (D) paxilline. Data are mean ± S.E.M. for n = 4 in each treatment group. Significance was tested using Tukey-Kramer post hoc test after a repeated measures analysis of variance. Asterisks indicate the significance of each treatment in wild-type mice compared with the pre-drug control at time = 0. *, P<0.05; **, P<0.01; ***, P<0.001.
Figure 2.
Cardiovascular function in wild-type (C57 black), Kcnmb1−/−, Kcnmb1/b4−/−, and Kcnma1−/− mice treated with 8 mg/kg paxilline (Pax).
(A) Blood pressure and (B) Heart rate. ***, P<0.001 for significant differences between pre-treated and paxilline-treated heart rates. Significance was tested using least significant difference post hoc test after analysis of variance. All data are mean ± S.E.M. for n = 4 in each treatment group.
Figure 3.
The effect of paxilline and iberiotoxin on heart rate in the isolated rat heart.
(A) 1 µM paxilline (Pax) was added at time = 40 min and infused for 10 min, preceded by a control infusion of Krebs-Henseleit perfusion fluid with 0.1% DMSO (n = 5). (B) Heart rate before, during and after infusion at time zero of different concentrations of paxilline (1, 5 or 10 µM). The heart rate in response to paxilline is the average of the peak responses following treatment. Toxins dissolved in Krebs-Henseleit solution were perfused through the heart for 12 min. Significance was tested using least significant difference post hoc test after analysis of variance. (C) Heart rate of isolated, perfused rat hearts infused with 0.23 µM iberiotoxin (IbTX) following a control infusion of Krebs-Henseleit fluid (n = 5). (D) Heart rate before treatment (saline control), at peak effect following infusion of iberiotoxin (n = 5), and following recovewry. Significance was tested using a paired Student's t-test. All data are mean ± S.E.M. *** P<0.001.