Beneficial effect of walnuts on vascular tone is associated with Akt signalling, voltage-dependent calcium channel LTCC and ATP-sensitive potassium channel Kv1.2

Abstract

Consumption of walnuts is beneficial for cardiovascular health. To study walnut effects on proteins involved in vascular tone regulation, control and fructose-fed rats were subjected to walnut diet for 6 weeks. In contrast with increased energy intake and body mass gain, aortic protein level of L-type calcium channel alpha subunit was decreased and the level of SUR2B subunit of ATP-sensitive K + channel was increased in healthy rats subjected to walnuts, together with improved Akt phosphorylation. Upon the walnut diet in rats subjected to fructose overload, the rise in energy intake and body mass gain, was followed by an increase in blood insulin. Although SUR2B level was elevated, the level of sodium-calcium exchanger NCX1 and inducible nitric oxide synthase were reduced and increased, respectively. In summary, walnut consumption was accompanied with moderate beneficial vascular effect in healthy rats, while an effect of walnut in rats with metabolic disturbances was rather controversial.

Walnut Supplementation Restores the SIRT1‐FoxO3a‐MnSOD/Catalase Axis in the Heart, Promotes an Anti‐Inflammatory Fatty Acid Profile in Plasma, and Lowers Blood Pressure on Fructose‐Rich Diet

“…Effects of walnut consumption on BP lowering in FRD rats may be related to the rich cation content, such as magnesium and potassium [ 44 ] and high content of ALA [ 10 ], which induces coronary VSMC relaxation [ 45 ]. The observed effect of walnut consumption on BP could be in association with its beneficial effect on the vascular tone, through the ATP-sensitive potassium channel, recently presented in the same model of FRD rats [ 40 ].…”

Fructose‐rich diet and walnut supplementation differently regulate rat hypothalamic and hippocampal glucose transporters expression

“…30,31 Interestingly, our results indicate that walnut supplementation in combination with fructose consumption restored hypothalamic membrane GLUT1 and GLUT3 contents to the control levels. Previously, we demonstrated that animals fed fructose, walnuts or combined diets exhibited similar serum glucose levels 17 . Keeping this in mind, our current results imply that in the presence of systemic normoglycemia there was an increased neuronal hypothalamic glucose utilization via GLUT3 under different types of diets, which appears to be abolished in the case of combined treatment.…”

“…We previously investigated the impact of walnut intake and fructose-rich diet on feeding behavior and metabolic parameters of animals used in this study and demonstrated that both individual and combined dietary regimes increased total calorie intake, body weight and adiposity. 17,18 Animals subjected to the fructose-rich diet were characterized by normoglycemia, elevated serum insulin and dyslipidemia, validating the development of fructose-induced metabolic syndrome. Additionally, we have characterized fatty acid composition under different dietary interventions across rat plasma, liver and adipose tissue.…”

“…Briefly, these animals displayed normoglycemia, elevated serum insulin and triglyceride levels, and increased adiposity and body weight. 17,18 Walnut kernels were administered at a dose of 2.4 g per day for 6 weeks. Special care was taken to ensure that each animal regularly consumed a provided daily dose of walnut kernels.…”

“…16 Most recently, moderately favorable vascular effects in metabolically challenged rodents were demonstrated following walnut consumption. 17 Additionally, irrespective of metabolic burden, dietary walnuts improved fatty acid composition profiles across plasma, liver, kidney and adipose tissue. 18 Considering that walnuts represent dietary source of polyunsaturated fatty acids (PUFA) that are involved in modulation of brain function, it is not surprising that walnut consumption has been associated with improved cognitive and motor performance and decreased neuroinflammation.…”