ABSTRACT
We investigated the effects of visceral stimulation by colorectal distension (CRD) on mean arterial blood pressure (MAP) and renal sympathetic nerve activity (RSNA), the latter being an index of vasoconstrictor activity, in anesthetized central nervous system (CNS)-intact and C2 spinalized rats. The CRD stimulation was induced by the distention of a balloon inserted into the colorectum. In CNS-intact rats, there were significant reductions in MAP and RSNA in response to intraballoon pressures of 60 and 80 mmHg, but not to 20 and 40 mmHg. However, spinalized rats demonstrated significant increases in MAP in response to intraballoon pressures of 60 and 80 mmHg and increases in RSNA in response to intraballoon pressures of 40, 60, and 80 mmHg. These results suggest that noxious visceral stimulation at lower spinal levels reduces MAP by inhibiting sympathetic output in CNS-intact anesthetized rats. On the other hand, noxious visceral stimulation results in an increase in sympathetic-induced MAP in spinalized anesthetized rats.
Subject(s)
Blood Pressure/physiology , Colon/innervation , Kidney/innervation , Rectum/innervation , Reflex/physiology , Sympathetic Nervous System/physiology , Anesthesia , Animals , Catheterization , Colon/physiology , Male , Physical Stimulation , Rats , Rats, Wistar , Rectum/physiology , Spinal Cord Injuries , Vagotomy , Vasoconstriction/physiologyABSTRACT
Electroacupuncture (EA) was applied bilaterally to the acupoints of Zu-san-li (ST-36) and Kun-lun (BL-60) in the hindlimbs of mice. The therapeutic effect of EA on inflammatory pain induced by an ipsilateral injection of complete Freund's adjuvant (CFA) into the right paw of the mouse was investigated in this study. The time of paw-withdrawal latency (PWL) was used as an indicator for judging the intensity of the pain induced by the CFA injection. The EA effects were divided into immediate (PWL tests within 2 h after EA treatment) and cumulative (PWL tests during and after repetitive EA treatments for 3 weeks) effects. As immediate effects, PWL was significantly shortened in the CFA-injected paw, but was again prolonged 20 min after an EA treatment and lasted until 30 min after. As cumulative effects, PWL was significantly shortened in the CFA-injected paw, but recovered from the 2nd to the 8th day during repetitive EA treatments. No such effects could be observed after sham EA treatment, which resulted in behavior similar to that in untreated animals. These results demonstrate that the CFA-induced inflammatory pain in mice is an ideal model system for the investigation of EA effects and may serve as a valuable reference for the clinical treatment of inflammatory pain in human beings. Furthermore, the mouse pain model opens the possibility to apply the investigation also to transgenic mice.
Subject(s)
Analgesia/methods , Electroacupuncture/methods , Pain Management , Acupuncture Points , Animals , Behavior, Animal/physiology , Complementary Therapies/methods , Disease Models, Animal , Freund's Adjuvant , Hindlimb/anatomy & histology , Hindlimb/innervation , Inflammation/physiopathology , Male , Mice , Mice, Inbred Strains , Pain/chemically induced , Pain/physiopathology , Synaptic Transmission/physiologyABSTRACT
Acupuncture treatment is one of the most desirable choices for the management of pain including chronic visceral pain, but its scientific evidence and laws of action are not very clear at this point. In this study, we examined the immediate and cumulative effects of electro-acupuncture (EA) on chronic visceral pain induced by colorectal distention (CRD) stimuli in rats using an irritable bowel syndrome (IBS) model (a chronic visceral hypersensitivity model). The results demonstrated that EA could significantly depress both abnormally increased abdominal withdrawal reflex (AWR) scores and the magnitude of electromyograms (EMGs) recorded from the rectus abdominis in response to CRD stimulation at strengths of 20, 40, 60, and 80 mmHg. Repeated EA treatment for 14 days showed that the effects of EA on both abnormal AWRs and EMGs appeared 2-4 days after the start of the EA application session, gradually enhanced to its maximum within 8-12 days, and lasted 5 days after EA treatment stopped. These data provide evidence that visceral pain associated with the rat IBS model can be effectively treated by EA and opens up the possibility of clinical treatment of chronic visceral pain with acupuncture.
Subject(s)
Electroacupuncture/methods , Hyperalgesia/therapy , Visceral Afferents/physiopathology , Animals , Behavior, Animal , Chronic Disease , Colonic Diseases, Functional/complications , Electromyography/methods , Hyperalgesia/etiology , Male , Pain Measurement/methods , Rats , Rats, Sprague-Dawley , Time FactorsABSTRACT
The girdled trunk of Eucommia ulmoides, sometimes could not regenerate a new bark due to ringed surface necrosis. But, if an extension of 10cm of the bark on each end of the necrotic part was removed in time and re-covered with new bark taken from another tree, the re-covered bark and the newly girdled part could heal together one week after. Opposite to the necrotic surface the loose part of the re-covered bark regenerated callus from the phloem ray cells. If the re-covered part was very close to the necrotic surface, no callus was regenerated. However, many scattered tracheid-like elements derived from phloem were found. And then groups of cells including several tracheid-like elements were discernible. There was a ring of meristematic cells around that group of cells. Finally these meristems gradually became normal and had usual activities of vascular cambium.
