ABSTRACT
OBJECTIVE: This study investigated the effects of aqueous leaf extract of Tridax procumbens (ALETP) on contractile activity of corpus cavernosum in N-nitro-l-arginine methyl ester (l-NAME)-induced hypertensive male rats. METHODS: Twenty normal, adult male rats (130-150â¯g) were divided into four groups of five rats each. Group I (control) was given normal saline (0.6â¯mL/kg) and group II was given l-NAME (40â¯mg/kg) for 6â¯weeks. Groups III and IV also received l-NAME (40â¯mg/kg) for 6â¯weeks but were further co-treated with 100 and 200â¯mg/kg of ALETP, respectively, from week 4 to week 6. All treatments were given orally. Strips of corpus cavernosum from each of the four groups were exposed to increasing concentrations of acetylcholine (ACh) and sodium nitroprusside (SNP) (10-9-10-5mol/L) after contraction with phenylephrine (10-7â¯mol/L) to test for a dose-response effect. Response to potassium and calcium was also measured after cumulatively adding potassium and calcium (10-50â¯mmol/L) to potassium- and calcium-free organ chamber. Isometric contractions were recorded through an Ugo Basile data capsule acquisition system. RESULTS: Mean arterial blood pressure was significantly reduced in the ALETP co-treated group compared to the control and l-NAME-only groups (Pâ¯<â¯0.05). Cavernosa strips from ALETP co-treated rats exhibited significant inhibition of contraction in response to phenylephrine, potassium chloride, and calcium chloride (Pâ¯<â¯0.05). Relaxation in response to Ach and SNP was also significantly impaired in cavernosa strips from the l-NAME-only treated group (Pâ¯<â¯0.05), while ALETP co-treated groups showed enhanced percentage relaxation. CONCLUSION: ALETP treatment of l-NAME-induced hypertensive rats promotes a relaxant effect on isolated cavernosa strips. ALETP shows potential in correcting erectile dysfunction in hypertension.