From the Dept. of Physiology, School of Medical Sciences, Tarbiat Modarres University, and the Dept. of Physiology and Biophysics, Baghiatollah University of Medical Sciences, Tehran, I.R. Iran.
Abstract: (3901 Views)
Previous studies have shown that electrical stimulation (ES) increases blood
flow, but the exact mechanisms are not clear. The present study was designed to
clarify some of the underlying mechanisms involved in this phenomenon. White
adult rabbits Lt.-6 months old were used. Animals were anesthetized by sodium
pentobarbital (40 mg/kg, IV) and skin blood flow in the thoracic back was recorded
using a Laser Doppler flowmeter (LDF). Square waves (20 Hz frequency, 0.5 ms
duration, 15 V strength) were applied through a pair of surface electrodes placed
on the skin of animals. Drugs were applied to the skin close to the tip of the laser
optic probe. The results obtained were as follows: 1. Electrical stimulation
increases local blood flow. 2. Blood flow increases dose-dependently by
administration of substance P (SP). 3. The response of ES on local blood flow was
augmented in the presence of SP. 4. SP-antagonists did not have any effect on basal
local blood flow. 5. The effect of ES was attenuated in the presence of SP-antagonists,
but this was not statistically significant. 6. Local blood flow increased
in reserpinized animals. 7. The electrically-induced increase in blood flow in
reserpinized animals was not statistically different from that of non-reserpinized
animals. Based on the above findings, it could be concluded that release of
vasodilating compounds such as SP from sensory nerve endings may contribute in
electrical stimulation and increase blood flow.