Increased cerebral blood flow in rats when exposed to an ultra-low frequency magnetic field
Abstract
Ultra-low frequency magnetic fields (ULF) in their pulsed and sinusoidal forms are being studied as a possible method of stroke treatment. It has been shown that the therapeutic effect is mediated by an increase in the production of nitric oxide, presumably of endothelial origin (eNO). Meanwhile, there is a way to judge with a higher degree of probability about eNO – this is a wavelet analysis of fluctuations in microcirculatory blood flow. The purpose of this study was to identify the effect of SNMP on cerebral blood flow and its amplitude-frequency characteristics associated with eNO.
Materials and methods. The experiments were performed on white sexually mature male rats weighing 250-300 g of the Wistar line under anesthesia (chloral hydrate, 400 mg/kg, IV). The animal was placed in a solenoid, in which a SNMP with a magnetic induction of 2.34 Gauss was created, varying according to a sinusoidal law with a frequency of 15 Hz and an amplitude of 127 mA. Registration of local cerebral blood flow (MC) in the parietal neocortex (in a tissue volume of 0.5 mm3) was carried out with a laser Doppler monitor LAKK-02 (NPP "LAZMA", Russia). 480-second recordings were used for spectral wavelet analysis of oscillations. The following spectrum parameters were evaluated: endothelial (0.01–0.04 Hz), neurogenic (0.04–0.15 Hz), myogenic (0.15–0.4 Hz), cholinergic (0.4–0.6 Hz), respiratory excursions (0.4–2.0 Hz), and cardiac (pulse wave, 2.0–4.0 Hz).
Results. In the control series, 1 hour after the animal was in an idle solenoid, the MK and amplitude of the rhythms did not change. In the experimental series, 1 hour after exposure to SNMP, the amplitudes of MK oscillations in the endothelial, neurogenic and respiratory ranges increased significantly (by 80%, 79% and 20%, respectively), and MK increased by 11.4% (p<0.003).
Conclusion. Stimulation of the rat's SNMP body has several beneficial effects: an increase in cerebral blood flow and an increase in the amplitudes of MC oscillations in the respiratory, neurogenic and endothelial ranges. An increase in MC when exposed to SNMP may occur due to a decrease in adrenergic effects on cerebral arterioles and activation of eNOS.
