The effects of AII, ACE inhibitors and AT1 blockers on the isolated guinea pig vas deferens contractions was studied in the presence of electric stimulation. AII was used in concentrations 10-8, 10-7, 10-6, captopril and lisinopril in 10 μM, 50μM, 100 μM solutions were administrated in vitro, while lisinopril, ramipril, telmisartan and cardesartan were administrated in vivo. The contraction amplitude was reduced by each ACE inhibitor and AII receptor blocker, while in the presence of AII the contractions amplitude of the contraction was significantly increased.