To complete the picture, we consider the potentials of vascular origin, which can contribute to the magnitude of SCP. Partially, we touched on this issue when considering the potential of the BBB. The potential difference arises not only in the area of cerebral capillaries, but also in other blood vessels, and the inner surface of the vessel wall is negatively charged with respect to the external one .
In the last two decades, ideas about the electrical potentials of the vascular system and their role in the energy metabolism of the body have expanded significantly. It was shown in the works that the walls of arteries and veins function as electrical insulators surrounding the electrically conductive blood plasma. At the level of the capillaries, an electrical contact is made between blood plasma and tissue fluid, which, like plasma, is electrically conductive.
The vessel wall consists of an endothelium directly adjacent to the lumen of the vessel. In addition to the endothelium, in all vessels, except for capillaries, there are elastic and collagen fibers, as well as smooth muscle cells. Arterial endothelial cells form a layer with high resistance. KA Stanness et al. (1996) showed that aortic cells grown in culture together with astrocytes form a selective barrier with a specific electrical resistance of 2.9 kΩ cm 2 , which is approximately an order of magnitude higher than the corresponding parameter for a neuron membrane. According to K. Miao et al. (1993), the electrical resistance of endothelial cells of veins and arteries is 10-240 Mom, it is assumed the presence of electrical interaction between endothelial cells. Vascular resistance depends primarily on the condition K, + Na + Spoken catch .
The main effect on the potentials of blood vessels is exerted by the ionic composition of the blood, in addition, they are affected by the potentials of smooth muscle cells, the degree of expansion of the walls of the vessel, the speed of blood movement, etc. Between the outer and inner surfaces of endothelial and smooth muscle cells there is a potential difference of the order of several tens of millivolts, depending on the ionic environment of the cell, ATP content and other factors. A change in blood pH in the vessels affects the ion channels (K + , Na + Cl – ), and also affects the operation of the Na + / H + pump, which changes the polarization of endothelial cells and, possibly, the potentials of smooth muscle fibers. A change in pH affects the value of the membrane potentials of the smooth muscles of cerebral arteries, affecting vasodilation .
The effect of the ionic composition of the blood on the potential of the vascular wall is determined mainly by the diffusion potential, the occurrence of which is associated with different concentrations of ions outside and inside the vessel and, possibly, in different parts of the circulatory system. Due to the fact that the capillary walls are permeable to H + ions, these ions play a significant role in potential formation. The potential difference between the outer and the inner wall of the vessel varies according to the Nernst equation, wherein with increasing content of H + in the positive potential blood outer surface of the vessel increases i .
The effect of alkalosis or acidosis of peripheral blood on vascular potentials can be easily demonstrated in the following experiments.
1. The potential difference between the wrists of the right and left hands was measured. Then acidosis was created in the blood of the left hand. To do this, the venous outflow was violated in this hand by clamping it with a tonometric cuff with a pressure lower than the systolic and higher than the diastolic and asked the subject to do a little work with the hand of this hand (squeeze and unclench the fist several times). At the 3-4th minute, a positive shift of the potential difference of about 2 mV with respect to the free arm was recorded on the clamped arm.
2. In the blood of the left hand, alkalosis was created using hyperventilation, in which the leaching of CO 2 occurs . To prevent the development of alkalosis in the right hand, the flow of blood into it was limited for 1 min. using a tonometric cuff, creating pressure above systolic. Control experiments showed that in the absence of hyperventilation, clamping with a tonometric cuff of one of the hands for 1 min. did not change the potential difference between the hands. During hyperventilation, a negative shift in the potential difference of up to 3 mV on the arm with an alkaline pH shift in the blood relative to the other arm was recorded.
These experiments indicate the dependence of the potential difference on the pH in the blood of both hands. A change in the potential difference — a positive shift in case of acidosis in the blood and a negative shift in alkalosis — corresponds to the dynamics of the potential under the influence of a change in the concentration of hydrogen ions in the blood, taking into account the extravascular location of the recording electrodes. Indeed, with the accumulation of hydrogen ions inside the vessel, an increase in potential occurs extravasally; with a decrease in the concentration of hydrogen ions in the blood, a negative potential shift is observed on the outer surface of the vessels.
A potential difference sensitive to the concentration of hydrogen ions was also detected at the placental border separating blood with different pH. So, between the blood of the mother and the fetus, a potential difference of 14 to 93 mV is recorded, and the mother’s blood is positive in relation to the fetus (corresponding to the fact that the blood of the fetus is more acidic). With an increase in acidosis in the fetal blood, the potential difference also increases . The regularity of the dynamics of this potential difference indicates its diffusion nature.
The polarization of the vascular wall performs a certain useful function. It was found that the electronegativity of the inner walls of blood vessels prevents thrombosis, repelling negatively charged platelets in a healthy vessel and, conversely, attracting platelets when the vascular wall is damaged. Similarly, negatively charged white blood cells migrate to the area of inflammation.
U of view , the electric potentials of the vascular system plays an important role in energy metabolism of the body, taking part in the transport of ions in the blood vessels and tissues. The significance of this discovery is compared with a description of the circulatory system by W. Harvey. The author showed that in oncological diseases, disturbances in the system of electrical circulation significantly affect oncogenesis. It is assumed that the circulation of energy along the meridians is associated with this system, and that the therapeutic effect of acupuncture is carried out with the participation of electrical potentials of vascular origin and is aimed at normalizing energy metabolism. It is no accident that acupuncture points differ in electrical characteristics from surrounding areas. It is assumed that meteosensitivity is largely due to changes in vascular potentials in violation of external electromagnetic fields.