Animals ; Electric Stimulation ; Hippocampus ; physiology ; Male ; Nerve Endings ; physiology ; Rats ; Rats, Sprague-Dawley ; Vagus Nerve ; physiology

Full evidence and obvious reasons made it possible to arrive at the conclusion that the nature of transmission upon cerebrospinal neurons is overwhelmingly mechanical, not only in the periphery- between various receptors and afferent nerve terminals, and between surrounding tissues and free nerve endings- but also in the cerebral cortex. When viewed from the standpoint of the everchanging patterns of natural mechanical stimuli, the neurons in the conscious cerebral cortex and the pain endings in an acute inflammatory locus have the same situation very much in common. It is quite likely that natural mechanical stimuli dominate over cerebrospinal nervous phenomena and physiologists have been watching the missing mechanism at work in every experiment upon afferent nerve terminals and cerebral cortex that they have done. The terms "psychic tension" and "central excitatory state" comparable to muscular tonus are of interest because they involve the use of mathematical techniques in psychology and neurophysiology. They are capable of becoming weak or strong, and they serve as an inner stimulus to give impetus to behavior. Unfortunately, however, it is an elusive inner stimulus, and it defies a lucid definition. But natural mechanical stimuli embody the psychic tension and the central excitatory state ultimately. It seems now that we just found a place where constant complaints against neurophysiology and physiological psychology are ventilated. We may conclude that natural mechanical stimuli are the leading direct stimuli to cerebrospinal neurons in the human body, and the plastic and developmental nervous phenomena and mental phenomena can be explained objectively by a familliar datum of mechanical energy and that we can reasonably expect the day of regarding material world and spiritual world in the monistic conception of matter-energy system.
Animals ; Anura ; Cerebral Cortex/*physiology ; Human ; In Vitro ; Motor Neurons/physiology ; Nerve Endings/physiology ; Receptors, Sensory/*physiology ; Spinal Cord/*physiology

Intraganglionic laminar endings (IGLEs) have been supposed to be the mechanoreceptors in the gut by electrophysiological recording techniques. But the specialized morphology of IGLEs could not be displayed closely associated with this function and the mechanism that IGLEs act as the mechanotransduction sites in the gut is not yet well understood. In the present study, we used styryl dye FM1-43 combined with stretch stimulation in the guinea pig esophagus to test whether IGLEs acted as the mechano-sensitive receptors of the vagal afferent nerves. At the same time, the special structure of IGLEs displayed by FM1-43 was further confirmed by neurobiotin anterograde labeling technique. To further investigate the characteristics of IGLEs as mechanosensitive receptors, different drugs were used to block or stimulate IGLEs activation. Our results indicated that only in the stretched preparation could FM1-43 enter the IGLEs and completely display their specialized structure, which was consistent with that shown by neurobiotin. The amount of IGLEs shown by stretch-evoked FM1-43 staining was much more than that shown without stretch stimulation [(90.4 +/- 9.5) % vs (10.7 +/- 2.1) %, P<0.05]. Ca(2+), TTX (0.6 mumol/L), atropine (0.6 mumol/L), SKF (50 mumol/L), and gadolium (100 mumol/L) had no effect on the IGLEs activation. But for benzamil (100 mumol/L), an epithelial sodium channel blocker, activation of IGLEs by stretch stimulation was significantly blocked. The potent ATP analogue, alpha,beta-methylene ATP (100 mumol/L) could not activate FM1-43 staining without stretch. These results indicate that IGLEs are sensitive to mechanical stimulation. This could lead to the deduction that IGLEs act as the mechanoreceptors of vagal afferent nerve. IGLEs could transmit mechanical stimuli directly through ion channels, independent of neurotransmitter release and action potential propagation. The stretch-sensitive channels on IGLEs probably belong to the epithelial sodium channel family rather than voltage-gated sodium ion channels. Furthermore, styryl dye FM1-43 is a useful activity-dependent marker to demonstrate the structure and function of IGLEs in guinea pig esophagus.
Afferent Pathways ; physiology ; Animals ; Esophagus ; innervation ; Female ; Ganglia, Autonomic ; physiology ; Guinea Pigs ; Male ; Mechanoreceptors ; physiology ; Nerve Endings ; physiology ; Vagus Nerve ; physiology

OBJECTIVETo determine the effect of tension relaxation by small needle knife on the muscle tension and morphology changes of nerve terminals when sustained pressure was applied to muscular tissue.

METHODSRat gracilis muscles were exposed to pressure in vivo at 70 kPa for 2 hours. Sixty rats were divided into three groups: normal, control and experiment group respectively. In all rats except the six normal ones, the lower legs were considered as the control group, and the right left as experiment group. At day 1, 2 and 3, 9 rats from the two groups were randomly selected and sacrificed in order to determine the muscle tension change. At the same time, muscle histology and morphology changes of nerve terminals were observed.

RESULTSAbnormal tension increased in muscles under compression of 70 kPa. At the 1st and 2nd days, there were no significant differences between the two groups. Compared with control group, the tension was lower in experiment group, and there was statistically significant difference (P < 0.01) between the two groups. Exposure of striated muscle tissue to intensive and prolonged compression may pathologically alter its microstructure. Histological evaluation showed that this stiffening accompanied extensive necrotic damage. The changes could not be found in the nerve terminals.

CONCLUSIONDeep muscle tissue that undergoes prolonged compression may significantly increase its stiffness during acute injury. Tension relaxation applied by small needle knife can effectively reduce the mechanical load which is harmful to the whole tissue.

Animals ; Biomechanical Phenomena ; Female ; Male ; Medicine, Chinese Traditional ; Muscle Tonus ; Muscle, Skeletal ; innervation ; pathology ; physiology ; Nerve Endings ; pathology ; Pain Management ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the density and distribution of nerve endings and neuropeptide Y (NPY) in lumbar facet joints of patients with low back pain.

METHODSFifteen patients without low back pain were selected as control group (group A). Facet joint samples in group A were obtained during the operation or lumbar spinal canal tumor they suffered from. Those patients with low back pain were divided into three groups according to their different origins of pain, such as not from facet joint (group B, 15 patients) ,from facet joint only (group C, 20 patients), or from facet joint partially (group D, 20 patients). Different origins were determined by VAS after facet joint block. The density and distribution of nerve ending and neuropeptide in the capsular tissues were analyzed by a modified gold chloride staining and immunochemistry respectively.

RESULTSCompared with the ones in group A and B, the fact joints in group C and D were more inclined to be degenerated and got more nerve endings. NPY was expressed mainly in the facet joint of patients with low back pain in group C and D. In addition, there was a significant relationship between the distribution of nerve endings and NPY expression,while none of them were related with MRI Fujiwara grade of facet joint.

CONCLUSIONThese results suggest that the number of mechanoreceptors, neural sprouting and secreted peptides in the facet joint capsules vary with the change of mechanical or nociceptive stimulation, which may promote the development of low back pain in return.

Adult ; Aged ; Case-Control Studies ; Chronic Pain ; etiology ; metabolism ; pathology ; Female ; Humans ; Low Back Pain ; etiology ; metabolism ; pathology ; Male ; Mechanoreceptors ; physiology ; Middle Aged ; Nerve Endings ; pathology ; Neuropeptide Y ; analysis