BACKGROUND/AIMS: Renal risks of nicotine exposure associated with hypercholesterolemia are still unknown. METHODS: Thus, hypercholesterolemic rats (HC) and their control (C) were evaluated by inulin clearance (InCl) measured at baseline and during nicotine infusion (100 microg/kg b.w.). Five groups were studied: (i) C; (ii) DEN (C submitted to a renal denervation); (iii) C + L-arginine (0.25% in drinking water); (iv) HC, and (v) HC + L-arginine (0.25% in drinking water). Furthermore, C and HC had their renal blood flow (RBF) measured and they have also been chronically treated with nicotine (12.5 microg/ml in drinking water) to assess InCl on the 8th day. RESULTS: Nicotine increased blood pressure in C, DEN and HC and reduced InCl only in C. L-Arginine treatment blunted nicotine effects on blood pressure and increased InCl only in C. Moreover, nicotine did not change RBF in C but elicited in HC, whereas renal vascular resistance was increased in C and unchanged in HC. Indeed, chronic nicotine exposure has also reduced InCl in C. CONCLUSION: Nicotine acted on the adrenergic system and nitric oxide counteracted this action in C, but the same may not be applied to HC. An impairment in renal autoregulation may explain why InCl was unchanged in HC. Copyright 2009 S. Karger AG, Basel.
BACKGROUND/AIMS: Renal risks of nicotine exposure associated with hypercholesterolemia are still unknown. METHODS: Thus, hypercholesterolemicrats (HC) and their control (C) were evaluated by inulin clearance (InCl) measured at baseline and during nicotine infusion (100 microg/kg b.w.). Five groups were studied: (i) C; (ii) DEN (C submitted to a renal denervation); (iii) C + L-arginine (0.25% in drinking water); (iv) HC, and (v) HC + L-arginine (0.25% in drinking water). Furthermore, C and HC had their renal blood flow (RBF) measured and they have also been chronically treated with nicotine (12.5 microg/ml in drinking water) to assess InCl on the 8th day. RESULTS:Nicotine increased blood pressure in C, DEN and HC and reduced InCl only in C. L-Arginine treatment blunted nicotine effects on blood pressure and increased InCl only in C. Moreover, nicotine did not change RBF in C but elicited in HC, whereas renal vascular resistance was increased in C and unchanged in HC. Indeed, chronic nicotine exposure has also reduced InCl in C. CONCLUSION:Nicotine acted on the adrenergic system and nitric oxide counteracted this action in C, but the same may not be applied to HC. An impairment in renal autoregulation may explain why InCl was unchanged in HC. Copyright 2009 S. Karger AG, Basel.