Calcitonin is a peptide hormone involved primarily in the regulation of calcium homeostasis. However,clinical observations have shown that calcitonin does in fact possess an analgesic effect in a variety of painful disorders. So I studied the analgesic effect of intracerebroventricularly(i.c.v.) administered salmon calcitonin(s-CT) using the hot plate test and writhing test. The influence on the analgesia induced by morphine and naloxone reversibility was also studied. When s-CT was administered i.c.v., analgesia was observed in both tests,although it was greater in the writhing test than in the hot plate test. The analgesic effect of s-CT was partially but significantly reversed by naloxone. Thus, these results provide information about the antinociceptive effect of s-CT via interaction with both opiate and non-opiate mechanisms.
Analgesia* ; Calcitonin ; Calcium ; Homeostasis ; Morphine* ; Naloxone ; Salmon

BACKGROUND: The pathophysiological and neurochemical changes following spinal injury are not yet elucidated. This study was designed to evaluate the morphological changes of the dorsal horn of the spinal cord and profiles of pain behaviors following intraspinal injection of NMDA in rats. METHODS: Rats were randomized into three groups: a sham-operated control group and groups where the rats received 10 mM or 100 mM N-methyl-D-aspatate (NMDA) injected into their spinal dorsal horn. Following injection, hypersensitivity to cold and mechanical stimuli and excessive grooming behaviors were assessed serially for four weeks. Morphological changes of the spinal cord were evaluated four weeks after intraspinal injection. RESULTS: Few animals in the NMDA groups developed hypersensitivity to cold and mechanical stimuli. The number of groomers and the severity of excessive grooming were significantly higher in the 100 mM NMDA group than those values of the control and 10 mM NMDA groups. The size of the neck region (lamina III-IV) was significantly smaller in the 100 mM NMDA group than in the control and 10 mM NMDA groups. CONCLUSIONS: In conclusion, intraspinal injection of NMDA in rats leads to the pathological sequela in the spinal cord and to excessive grooming behavior. These results support the use of NMDA and excessive grooming behavior after excitotoxic SCI as a model to study chronic pain after SCI.
Animals ; Chronic Pain ; Cold Temperature ; Grooming ; Horns ; Hypersensitivity ; Injections, Spinal ; N-Methylaspartate ; Neck ; Pilot Projects ; Rats ; Spinal Cord ; Spinal Cord Injuries ; Spinal Injuries

BACKGROUND: The implementation of intraoperative normovolemic hemodilution is a strategy used in an attempt to diminish the need for or obviate allogeneic transfusion and to avert the potential complications. The goal of this study was to evaluate the safety and efficacy of moderate intraoperative normovolemic hemodilution. METHODS: Fifteen patients scheduled for posterolateral spinal fusion underwent intraoperative normovolemic hemodilution with 10% pentastarch to a target hematocrit level of 25% (hemodilution group). All units of blood procured by hemodilution and additional allogeneic blood was transfused in the perioperative period to maintain the hematocrit level of>25%. We investigated the effect of hemodilution on whole blood coagulation as measured by the thromboelastography and, evaluated its efficacy of decreasing the need for allogeneic blood transfusion as compared to the nonhemodilution group, retrospectively. RESULTS: Hemodilution with pentastarch caused a decrease in response and coagulation time (p<0.01) but did not influence on the alpha angle and maximum amplitude on thromboelstogram. Amount of transfusion of allogeneic blood was 4.1 1.7 units for the hemodilution group and 5.0 1.5 units for the nonhemodilution group. Net red blood cell volume ""saved"" from hemodilution was about 120 ml. CONCLUSION: Moderate intraoperative normovolemic hemodilution with pentastarch does not affect the coagulability of whole blood. But its efficacy of decreasing the need for allogeneic blood transfusion is minimal.
Blood Coagulation ; Blood Transfusion ; Erythrocytes ; Hematocrit ; Hemodilution* ; Humans ; Hydroxyethyl Starch Derivatives ; Perioperative Period ; Retrospective Studies ; Spinal Fusion* ; Thrombelastography

BACKGROUND: It is emphasized that repetitive stimulation of small diameter afferent fibers produces a progressive increase in the action potential discharge and a prolonged increase in the excitability of neurons in the spinal cord following the stimulus and that this facilitatory component has a unique pharmacology. To investigate the behavioral parallels of this spinal facilitation, we evalusted the antinociceptive effects of intrathecal morphine, N-methyl-D-aspartate(NMDA), (+)-5-methyl-10,11- dihydro-5H-dibizo(a,d) cycloheptene-5, 10-imine hydrogen maleate(MK801) and (+/-)-3-(2-carboxy- piperazine-4-yl)-propyl-I-phosphonic acid(CPP), on the formalin test in rats. METHODS: Four to six days after chronic lumbar intrathecal catheterization, normal saline, morphine(0.1 to 30 ug), MK801(0.1 to 10 ug), CPP(0.1 to 5 ug) or NMDA(10 or 100 ng) were administered intrathecally before formalin injection. Spontanesous flinches were observed at 1-2 and 5-6 min(phase 1) and at 10 min intervals thereafter for 50 min(phase 2) after subcutaneous formalin injection into the dorsum of the right hind paw for each drug treated rats. RESULTS: Intrathecal morphine produced dose dependent inhibition of the phase 1 and phase 2 response(ED50=0.63 ug and 0.37 ug, respectively). Intrathecal MK801(0.1 to 10 ug) and CPP(0.1 to 5 ug) inhibited the phase 2 response more strongly than phase 1 response and inhibition of the phase 2 response(P<0.05 at any dose) was dose dependent(ED50=0.54 ug for MK801 and 0.15 ug for CPP). 1ntrathecal NMDA(10 or 100 ng) produced augmented responses in the intermediate and phase 2(P<0.05), but had no effect on the phase 1 response(P>0.7). Relative potencies of MK801 and CPP when compared with morphine were 1.34 and 0.41, respectively. CONCLUSIONS: This study suggests that intrathecal morphine and NMDA receptor antagonist(MK801 and CPP) have an antinociceptive effect on pathological pain mediated by central sensitization and that NMDA receptor antagonists can be utilized selectively in the treatment of components of central sensitization.
Action Potentials ; Analgesics ; Animals ; Catheterization ; Catheters ; Central Nervous System Sensitization ; Dizocilpine Maleate* ; Formaldehyde* ; Hydrogen ; Morphine* ; N-Methylaspartate* ; Narcotics ; Neurons ; Pain Measurement* ; Pharmacology ; Rats* ; Spinal Cord

No abstract available.

No abstract available.

No abstract available.

BACKGREOUND: Capsaicin acts specifically on a subset of primary sensory neurons involved in nociception. In addition to its excitatory actions, capsaicin can have subsequent antinociception and anti-inflammatory effects due to pharmacological, functional desensitization and axonal degeneration. Because capsaicin has selective actions on unmyelinated C and thinly myelinated Adelta primary sensory neurons, it can be speculated that intrathecally adminstered capsaicin results prolonged analgesia without adverse effects related to the destruction of the nonnociceptive nerve fibers. METHODS: We performed experiments to investigate the effects of capsaicin on electrophysiological responses of acutely dissociated rat dorsal root ganglion neurons and pain-like behaviors, such as tail flick responses to hot water (53 degrees), formalin-induced hyperalgesic responses and allodynic responses induced by peripheral nerve injury. RESULTS: Capsaicin affects preferentially small- to medium-diameter rat dorsal root ganglion neurons. In capsaicin responsive cells, superfusion with capsaicin evoked membrane potential depolarization and large inward currents. Cellular excitablity was continuously suppressed even after 3 min wash-out. Intrathecally administered capsaicin had no effect on tail withdrawal latencies, but flinching responses induced by subcutaneous formalin and allodynic responses induced by peripheral nerve injury were suppressed by capsaicin. CONCLUSIONS: The results suggest that capsaicin which acts on primary sensory neurons carrying nociceptive information is effective in managing pain induced in a pathological condition, such as inflammatory and neuropathic pain. The data may also be applicable for seeking novel pharmacological strategies for managing intractable pain, i.e. chemical neurolysis.
Analgesia ; Animals ; Axons ; Capsaicin* ; Formaldehyde ; Ganglia, Spinal ; Membrane Potentials ; Myelin Sheath ; Nerve Block ; Nerve Fibers ; Neuralgia ; Neurons ; Nociception ; Pain, Intractable ; Peripheral Nerve Injuries ; Rats* ; Sensory Receptor Cells* ; Water

No abstract available.
Animals ; Calcium* ; Clonidine* ; Ganglia, Spinal* ; Rats* ; Spinal Nerve Roots* ; Tetracaine*

While intrathecal morphine in small doses has been effective in controlling postoperative pain, many patients have been suffered from the side effects. In recent studies, it has been suggested that small dose of propofol can attenuate these side effects of intrathecal morphine. We have studied the effect of propofol and tried to find the optimum dose that can reduce side effects of intrathecal morphine. Sixty patients of ASA class 1 scheduled for anorectal surgery were allocated randomly to receive either a bolus dose of propofol 0.5 mg/kg followed by an infusion of 1 mg/kg/24hr(group Pl) or 2 mg/kg/24hr(group P2) and no bolus dose followed by 1,000 ml 5% dextrose water(control group). In this study, postoperartive sedation, nausea, vomiting, pruritus and urinary retention were evaluated immediate postoperatively, 12 hour, 24 hour and 48 hour after spinal anesthesia using 1% tetracaine 5 mg with 10% dextrose water 5 ml and morphine 0.3 mg. As time passed, all the complications subsided significantly. However, there was no significant difference among 3 groups except pruritus. The incidence of pruritus was lower in the group P1 and group P2(80%, 50% respectively) than the control group(90%). In the 12 hour-after evaluation, there was no patient of grade 3 pruritus in the group P2 but 5 patients in the control group(p<0.001) and 3 patients in the group Pl had itching(p<0.05). The higher doses of propofol, the greater sedative effect observed. However, there was no clinicaliy serious problem (e.g. respiratory depression, deep sedation). In conclusion, we recommend that an adequate infusion dose of propofol for reducing the incidence and severity of pruritus is 2 mg/kg/24hr.
Anesthesia, Spinal ; Glucose ; Humans ; Hypnotics and Sedatives ; Incidence ; Morphine* ; Nausea ; Pain, Postoperative ; Propofol* ; Pruritus ; Respiratory Insufficiency ; Tetracaine ; Urinary Retention ; Vomiting ; Water