Single-walled carbon nanotubes modulate cardiovascular control in rats.

Effect of water dispersible single-walled carbon nanotubes on the medullary cardiovascular control was studied in normotensive (control) and spontaneously hypertensive rats using physiological and biochemical approaches. We have shown for the first time the possible contribution of nitric oxide (NO) to single-walled carbon nanotube-induced effects in the cardiovascular nuclei of the medulla oblongata (the lateral reticular nucleus and nucleus ambiguous). The data of biochemical experiments indicate that single-walled carbon nanotubes added to the medulla oblongata homogenates induce an enhancement of constitutive nitric oxide-synthase (cNOS) activity, which is mostly neuronal nitric oxide-synthase (nNOS) in the brain, and an increase in the level of nitrite (NO-2), a stable nitric oxide metabolite which serves nitric oxide bioavailability marker. In physiological experiments, it has been revealed that effects of single-walled carbon nanotube injection in the cardiovascular nuclei under study are attenuated after preliminary nNOS inhibiting. An analysis of single-walled carbon nanotube-induced changes in the levels of malonic dialdehyde, an oxidative stress marker, as well as the levels of reactive nitrogen species (pools of nitrate anions), and the activity of Ca2+-independent inducible nitric oxide synthase (iNOS) has indicated that single-walled carbon nanotubes used in the study do not promote oxidative and nitrosative stress in control and spontaneously hypertensive rats. [ABSTRACT FROM AUTHOR]