RT - Journal Article T1 - Effects of Low Level of Lead Exposure on Responsiveness of The Rat Isolated Heart to Adrenergics JF - IJT YR - 2009 JO - IJT VO - 2 IS - 4 UR - http://ijt.arakmu.ac.ir/article-1-61-en.html SP - 254 EP - 259 K1 - Adrenergic System K1 - Contractility K1 - Hypertension K1 - Lead Acetate AB - Background: There are controversial reports about the exact mechanisms of lead-induced hypertension, but many factors such as alteration in the responsiveness of cardiovascular system to endogenous substances including catecholamines could be one of the mechanisms involved. In present study, the effect of exposure to 100 ppm lead acetate by drinking water (in the periods of 4, 8 and 12 weeks) on the responsiveness of rat isolated beating heart to β-adrenergics was investigated, using Langendorff isolated heart setup. Methods: The isolated hearts were perfused with Krebs-Henseleit solution at 37˚C and pH=7.4 and gassed with 95% O2 + 5% CO2. The rate (chronotropic) and contractile (inotropic) responses of the heart to β-adrenergics (isoproterenol and dobutamine) were recorded by adding these agents at multiple concentrations to the perfusion solution. Results: The blood pressure in 8- and 12-week lead-treated groups was significantly increased compared with those of the control group (P LA eng UL http://ijt.arakmu.ac.ir/article-1-61-en.html M3 ER -