Molecular mechanism and regulation of neurovascular coupling in the human brain: The influence of thermoheliox.

[Display omitted] • An experimental study of BOLD-signal dynamics before and after inhalations of thermoheliox was carried out using fMRI. • The biphasic nature of the hemodynamic response is based on the inhibition of the Ca2+ pulse by products causing vasodilation. • Preliminary inhalation with thermoheliox stimulates and prolongs hemodynamic pulses. • On the basis of the kinetic model, a parametric analysis of the process was performed. An experimental study of the dynamics of the BOLD (blood oxygen level dependent) signal by functional magnetic resonance imaging was carried out. It was found that the dynamic responses of the BOLD-signal, have a biphasic character. Through kinetic modeling methods, it was shown that the biphasic nature of the hemodynamic response is based on negative feedback, with Ca2+ pulse inhibited by vasodilation products (NO and prostaglandins). The effect of thermoheliox (inhalation of a mixture of helium and oxygen at 70 °C) on functional hemodynamics was studied. It was shown that preliminary inhalation of thermoheliox stimulates and prolongs hemodynamic impulses. [ABSTRACT FROM AUTHOR]