Pharmacological Actions of Naringin on Alpha,Beta-adrenoceptors and Uptake of Noradrenaline in Rat Isolated Vas Deferens

In normal Krebs solution, naringin (1×10⁻⁷ M sc–2×10⁻⁶ M ) enhanced noradrenaline-induced contractions in rat isolated vas deferens increasing this potentiation in a concentration dependent manner. This enhancing effect continued in the presence of yohimbine (10⁻⁶ M ) or propranolol (10⁻⁶ M ). Naringin did not modify significantly the dopamine dose-response curves. In a medium containing 10⁻⁸ M prazosin, naringin decreased noradrenaline dose-response curves underneath the control curve at all the doses tested. Naringin did not modify significantly the NA dose-response curve in a medium containing cocaine (10⁻⁵ M ) or oestradiol (10⁻⁵ M ). The potentiation produced by naringin on the NA-induced contractions in rat vas deferens may be due to alpha-1 receptor activation, together with an interference of naringin in catecholamine uptake process.