Dopaminergic, cholinergic and nitrinergic pathways implicated in blood pressure lowering effects of Saccharum officinarum L. (Sugarcane) on rats.

Abstract

BackgroundSaccharum officinarum L. (sugarcane), a grass belonging to the Poacea family, is widely cultivated in Brazil mainly to produce sugar and ethanol. According to ethnopharmacological data, the sugarcane is used in folk medicine for the treatment of cardiovascular diseases. Besides this, a previous study showed that there is a relationship between the pharmacological actions of sugarcane and the activation of dopaminergic and cholinergic pathways. Physiologically, it is well established that the blood pressure control could involve different neurotransmission systems, such as dopaminergic, cholinergic and nitrinergic. AimTo validate the cardiovascular actions of sugarcane preconized by traditional medicine and evaluate the possible participation of the dopaminergic, cholinergic and nitrinergic systems in its pharmacological mechanism of action. MethodsDried leaves were extracted with distilled water, concentrated, and lyophilized (AE). In vivo assays were performed in conscious rats to record systolic blood pressure (SBP) by the tail method after acute and subacute oral (gavage) administration of AE (10–500 mg/kg). The involvement of the cholinergic and dopaminergic pathways in AE responses was evaluated with administration (30 min) of atropine (5 mg/kg, i.p.) or haloperidol (0.5 mg/kg, i.p.), respectively. The participation of nitric oxide in the cardiovascular mechanism of action was evaluated in animals submitted to treatment with l-Name (60 mg/kg, p.o.). After installation of hypertension, animals were treated with AE. ResultsAcute and subacute treatment with AE reduced SBP in a dose-dependent manner, with greater pharmacological efficacy after administration of lower doses. Atropine and haloperidol inhibited the hypotensive effects of AE, and it was shown that in hypertensive animals, AE was ineffective in reducing SBP. ConclusionThis study revealed the blood pressure lowering effect of AE in a dose-dependent manner and demonstrated that the pharmacological cardiovascular effects of sugarcane involve dopaminergic, cholinergic and nitrinergic pathways.