ABSTRACT
On the intact and awake rat, the flexion reflex potential (FRP)and dorsal root potential (DRP) induced by stimulation of the cutaneous nerve with graded intensity stimulations to the sural nerve (a pure cutaneous nerve) were observed, there appeared A-FRP and C-FRP one after the other on the hamstring nerve (a group of nerves innervating the hindlimb flexors), and A-DRP and C-DRP on the L_5 dorsal root at the same time. The threshold and the latencices of A-FRP and A-DRP had no differences, and had significant positive correlations. The amplitudes of A-FRP and A-DRP increased simultaneously with the increase of the stimulating intensity in certain range. The threshold and latency of C-FRP are larger than those of C-DRP. The threshold and the latency of the C-FRP and C-DRP showed significant positive correlation. The amplitudes of C-FRP and C-DRP increased simultaniously with the increase of the stimulating intensity in certain range. The train stimuli (three pulses, 5ms interval, 0. 5ms duration) induced larger FRP and DRP than those induced by single stimulus. Thus, FRP and DRP both have the property of temporal summation.
ABSTRACT
Single unit activity were recorded from 157 dorsal horn neurons in the spinal rats by stimulation of left surat nerves. Stretching urinary bladder were performed after the neurons were identified by somatic afferents. 32 out of the 157 could also be activated by stretching urinary bladders. These recorded dorsal horn neurons which responded to both somatic and visceral inputs are called somatovisceral convergent neurons (SVCN). The afferent visceral fibers were N group according to conductive velocity in our experiment. It has been shown that C-fiber component in 9 WDR neurons were incresed by stimulating the left sural nerves after stretching urinary bladders. 15 spontaneous- discharge WDR neurons were recorded and 13 out of them were excited, meanwhile, 2 out of them were inhibited after urinary bladders were stretched. The study provides the new data for the convergence from the somatic and visceral afferents in the dorsal horn of spinal cord and supplies the first evidence for central mecha nism of visceral referred pain.
ABSTRACT
Deseription was given of the effect of electric acupuncture of Neiguan point on the flexion reflex potential (FRP) of the hindlimbs and the dorsal root potential (DRP). On the intact and awake rats, the graded train stimulation (three pulses, 5ms interval, 0.5ms duration) was given to the sural nerve (a pure cutancous n(?), the C-FRP and C-DRP with their proper amplitudes (70～80% maximum) were obtained on the hamstring nerve (a group of nerves innervating the hindlimb flexors) and L5 dorsal root respectively. Then the electric acupuncture with low freqency and low intensity (4Hz, 1～3V)and low freqency and high intensity ( 4Hz, 20～40V), lasting 5 minutes, was given to the ipsilateral Neiguan point. After acupuncture, the amplitudes of both C-FRP and C-DRP decreased without change of their latebcues. The former one declined heavier and recovered slower than the latter one did. The A-FRP and A-DRP were not affected. Te result of the experiment suggests that the ipsilatcral Neiguan point cletric acupuncture can induce hindlimb's analgesia, the presynaptic inhibition might be involved in the mechanism of such analgesia.