The effects of CPA and subsequent addition of specific mitochondrial drugs on the force of spontaneous contractions in uterine longitudinal smooth muscle. (A) While CPA (10 µM, n= 5–8) alone did not decrease the force of contractions, contraction amplitude was significantly decreased by addition of CCCP (2 µM, n= 5), rotenone (1 µM, n= 8), CGP37157 (10 µM, n= 7) but not kaempferol (Kaemp; 10 µM, n= 7). Columns represent the mean ± SEM. *Significantly different from control, #significantly different from CPA, Student's two-tailed paired t-test, P < 0.05. Dashed trace represents 100% control. (B) Depolarization and firing of action potentials and associated transient contractions caused by CPA (10 µM) was not obviously altered by addition of CCCP (2 µM). Action potential activity ceased after ∼10 min but was transiently re-initiated by brief application of high K+ solution. CCCP, carbonylcyanide-3-chlorophenylhydrazone; CGP37157, 7-chloro-5-(2-chlorophenyl)-1,5-dihydro-4,1-benzothiazepin-2(3H)-one; CPA, cyclopiazonic acid; DMSO, dimethyl sulphoxide.