Figure 6.

Effect of tachykinins on the Ca²⁺-induced contractions in the α-toxin permeabilized corpus cavernosum strips. In (a), 1 μM SP, NKA and NKB were applied in the presence of 10 μM GTP after the treatment with 10 mM EGTA relaxing solution for 10 min. In (b–d), the corpus cavernosum strips were precontracted by 300 nM Ca²⁺ and 10 μM GTP. The tissue was treated with 10 μM CPA for 10 min before and during the application of this solution. When the tension reached a steady state, 1 μM SP, NKA and NKB were applied. After the application of tachykinins, maximal tensions were induced by 10 μM Ca²⁺. The developed tension was expressed as a percentage, assigning the values in the relaxing solution ([Ca²⁺]_i<10 nM) and in the activating solution ([Ca²⁺]_i=10 μM; maximal tension) to be 0 and 100%, respectively.