Involvement of peripheral cannabinoid and opioid receptors in ß-caryophyllene-induced antinociception.

BACKGROUND: ß-caryophyllene (BCP) is a common constitute of the essential oils of numerous spice, food plants and major component in Cannabis. The present study investigated the contribution of peripheral cannabinoid (CB) and opioid systems in the antinociception produced by intraplantar (i.pl.) injection of BCP. The interaction between peripheral BCP and morphine was also examined. METHODS: The antinociceptive effect of i.pl. BCP was assayed by the capsaicin tests in mice. Antagonists for CB and opioid receptors, and antisera against ß-endorphin were injected peripherally prior to i.pl. injection of BCP. Morphine in combination with BCP was injected subcutaneously or intrathecally. RESULTS: The i.pl. injection of BCP dose-dependently attenuated capsaicin-induced nociceptive response. The antinociceptive effect produced by BCP was prevented by pretreatment with AM630, a selective CB2 receptor antagonist, but not by AM251, a selective CB1 receptor antagonist. Pretreatment with naloxone, an opioid receptor antagonist, and ß-funaltrexamine, a selective µ-opioid receptor antagonist, reversed the antinociceptive effect of BCP. Pretreatment with naloxone methiodide, a peripherally acting antagonist for opioid receptors and antisera against ß-endorphin, resulted in a significant antagonizing effect on BCP-induced antinociception. Morphine-induced antinociception was increased by a low dose of BCP. The increased effect of morphine in combination with BCP was antagonized significantly by pretreatment with naloxone. CONCLUSIONS: The present results demonstrate that antinociception produced by i.pl. BCP is mediated by activation of CB2 receptors, which stimulates the local release from keratinocytes of the endogenous opioid ß-endorphin. The combined injection of morphine and BCP may be an alternative in treating chemogenic pain.

Differential involvement of opioid receptors in stress-induced antinociception caused by repeated exposure to forced walking stress in mice.

We examined the effects of repeated exposure to forced walking stress for 6 h once a day for 0, 6 and 9 consecutive days on formalin-induced paw licking in mice. In each observation period, stress-induced antinociception (SIA) was observed only in the late phase (from 10 to 30 min), but not in the early phase (from 0 to 10 min) of formalin-induced paw licking in mice. Moreover, it was hard to develop tolerance even by daily exposure to stress for 6 days, although SIA for 9 days decreased compared with those for 0 and 6 days. Naloxone (10 mg/kg), an opioid-receptor antagonist, was effective in reducing the SIA induced by forced walking stress for 6 days and/or 9 days, but not for 0 days. Furthermore, the experiments with selective opioid-receptor antagonists, beta-funaltrexamine (mu) naltrindol (delta), or nor-binaltorphimine (kappa) demonstrated that SIA induced by forced walking stress for 9 successive days may be mediated through opioid delta- and kappa-receptors. Finally, although SIA seemed to be a unitary phenomenon, the present results strengthened the idea that SIA is induced by exposure to forced walking stress with characteristics dependent on the duration of exposure.

Role of histamine H(1) receptor in pain perception: a study of the receptor gene knockout mice.

To study the participation of histamine H(1) receptors in pain perception, histamine H(1) receptor knockout mice were examined for pain threshold by means of three different kinds of nociceptive tasks. These included assays for thermal nociception (hot-plate, tail-flick, paw-withdrawal), mechanical nociception (tail-pressure), and chemical nociception (abdominal constriction, formalin test, capsaicin test) which evoked pain by the activation in nociceptive Adelta and C fibers. The mutant mice lacking histamine H(1) receptors showed significantly fewer nociceptive responses to the hot-plate, tail-flick, tail-pressure, paw-withdrawal, formalin, capsaicin, and abdominal constriction tests. Sensitivity to noxious stimuli in histamine H(1) receptor knockout mice significantly decreased when compared to wild-type mice. This data indicates that histamine plays an important role in both somatic and visceral pain perceptions through histamine H(1) receptors. The difference in the effect of histamine H(1) receptors antagonist, the active (D-) and inactive (L-) isomers of chlorpheniramine on ICR mice further substantiates the evidence of the role of histamine H(1) receptors on pain threshold.

Evidence that N-terminal fragments of nociceptin modulate nociceptin-induced scratching, biting and licking in mice.

The intrathecal (i.t.) injection of 3.0 fmol nociceptin (orphanin FQ) elicited scratching, biting and licking responses in mice. N-terminal fragments of nociceptin, nociceptin (1-7), nociceptin (1-9) and nociceptin (1-13), induced no characteristic behavioral response. When these N-terminal fragments of nociceptin were injected simultaneously with nociceptin, the behavioral response induced by nociceptin was reduced dose-dependently. Nociceptin (1-13) was much more potent than nociceptin (1-7) and nociceptin (1-9) and antagonized nociceptin-induced response at equimolar doses. No significant effects of the N-terminal fragments were observed against the scratching, biting and licking response elicited by i.t. administration of substance P or N-methyl-D-aspartate. These results suggest that N-terminal fragments formed endogenously in the spinal cord may have an antagonistic effect on nociceptin-induced behavioral responses.

Effects of forced walking stress on formalin-induced paw licking in mice.

This study examined the effects of exposing mice to forced walking stress on formalin-induced paw licking. At each observation period (0.5-6 h) after exposure to forced walking stress, a significant antinociceptive effect (stress-induced analgesia, SIA) was observed only in the second phase (from 10 to 30 min), but not in the first phase (from 0 to 10 min) of formalin-induced paw licking in mice. The present data showed that SIA induced by exposure to forced walking stress was dependent on duration of the stress (0.5-4 h). SIA was dose-dependently antagonized by the NMDA receptor antagonist dizocilipine (0.01-0.04 mg/kg) but not by naloxone (10 mg/kg). Thus, the present results suggest that exposure to forced walking stress could cause SIA which may be involved in the nonopioid system via NMDA receptors.

Involvement of tachykinin NK1 receptors in nociceptin-induced hyperalgesia in mice.

Intrathecal (i.t.) injection of nociceptin at small doses (3.0 and 30.0 fmol) produced a significant hyperalgesic response as assayed by the tail-flick test. This hyperalgesic effect peaked at 15 min following i.t. administration of nociceptin (3.0 fmol) and returned to control level within 30 min. Hyperalgesia elicited by nociceptin was inhibited dose-dependently by i.t. co-administration of tachykinin NK1 receptor antagonists, CP-99,994 and sendide. A significant antagonistic effect of [D-Phe7, D-His9] substance P (6-11), a selective antagonist for substance P, was observed against the nociceptin-induced hyperalgesia. Pretreatment with i.t. substance P antiserum and i.t. capsaicin resulted in a complete block of the reduced threshold produced by nociceptin. The NK2 receptor antagonist, MEN-10,376 and pretreatment with neurokinin A antiserum did not alter the behavioural effect of nociceptin. The N-methyl-D-aspartate (NMDA) receptor antagonists, dizocilpine (MK-801) and D(-)-2-amino-5-phosphonovaleric acid (D-APV), and L-NG-nitro arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, failed to inhibit nociceptin-induced hyperalgesia. The results obtained suggest that the hyperalgesic effect of nociceptin may be mediated through tachykinin NK1 receptors in the spinal cord.

Nociceptin (1 - 7) antagonizes nociceptin-induced hyperalgesia in mice.

Nociceptin and its N-terminal fragment, nociceptin (1 7), were administered intrathecally (i.t.) into conscious mice. Nociceptin (3.0 fmol) produced a significant reduction in the nociceptive thermal threshold (hyperalgesia) measured as the tail-flick and paw-withdrawal responses. Nociceptin (1-7), injected i.t., at 150-1200 fmol had no significant effect. However, when nociceptin (1-7) (150 1200 fmol) was injected simultaneously with nociceptin (3.0 fmol), nociceptin-induced hyperalgesia was significantly reduced. Analgesia induced by a high dose (1200 pmol) of nociceptin was not antagonized by co-administration of nociceptin (1-7) (1200 fmol). These results suggest that N-terminal fragments of nociceptin formed endogenously could modulate the hyperalgesic action of nociceptin in the spinal cord.

Nociceptin-induced scratching, biting and licking in mice: involvement of spinal NK1 receptors.

1. Intrathecal (i.t.) injection of nociceptin at small doses (fmol order) elicited a behavioural response consisting of scratching, biting and licking in conscious mice. Here we have examined the involvement of substance P-containing neurons by using i.t. injection of tachykinin neurokinin (NK)1 receptor antagonists and substance P (SP) antiserum. 2. Nociceptin-induced behavioural response was evoked significantly 5 - 10 min after i.t. injection and reached a maximum at 10 - 15 min. Dose-dependency of the induced response showed a bell-shaped pattern from 0.375 - 30.0 fmol, and the maximum effect was observed at 3.0 fmol. 3. The behavioural response elicited by nociceptin (3.0 fmol) was dose-dependently inhibited by intraperitoneal (i.p.) administration of morphine. 4. The NK1 receptor antagonists, CP-96,345, CP-99,994 and sendide, inhibited nociceptin-induced behavioural response in a dose-dependent manner. A significant antagonistic effect of [D-Phe7, D-His9]SP (6 - 11), a selective antagonist for SP receptors, was observed against nociceptin-induced response. The NK2 receptor antagonist, MEN-10376, had no effect on the response elicited by nociceptin. 5. Pretreatment with SP antiserum resulted in a significant reduction of the response to nociceptin. No significant reduction of nociceptin-induced response was detected in mice pretreated with NKA antiserum. 6. The N-methyl-D-aspartate (NMDA) receptor antagonists, dizocilpine (MK-801) and D(-)-2-amino-5-phosphonovaleric acid (APV) (D-APV), and L-NG-nitro arginine methyl ester (L-NAME), a nitric oxide (NO) synthase inhibitor, failed to inhibit nociceptin-induced behavioural response. 7. off present results suggest that SP-containing neurons in the mouse spinal cord may be involved in elicitation of scratching, biting and licking behaviour following i.t. injection of nociceptin.

Differential involvement of mu-opioid receptor subtypes in endomorphin-1- and -2-induced antinociception.

We investigated the role of mu-opioid receptor subtypes in both endomorphin-1 and endomorphin-2 induced antinociception in mice using supraspinally mediated behavior. With tail pressure as a mechanical noxious stimulus, both intracerebroventricularly (i.c.v.) and intrathecally (i.t.) injected-endomorphins produced potent and significant antinociceptive activity. Antinociception induced by i.t. and i.c.v. injection of endomorphin-1 was not reversed by pretreatment with a selective mu1-opioid receptor antagonist, naloxonazine (35 mg/kg, s.c.). By contrast, antinociception induced by i.t. and i.c.v. endomorphin-2 was significantly decreased by mu1-opioid receptor antagonist. Antinociception of both i.t. and i.c.v. endomorphin-1 and -2 was completely reversed by pretreatment with beta-funaltrexamine (40 mg/kg, s.c.). The results indicate that endomorphins may produce antinociception through the distinct mu1 and mu2 subtypes of mu-opioid receptor.

Ion distribution in matrix parts of glass-polyalkenoate cement by SIMS.

The microstructure of the set glass-polyalkenoate cement has not been undertaken beyond a study where an Electron Probe Micro Analyser was used. The purpose of this investigation was to determine the ion distribution in matrix parts of the set cement by means of Secondary Ion Mass Spectrometry (SIMS). Among the techniques for surface and microscopic analysis, SIMS is said to be the one with the highest sensitivity. O2+ ions were used as the beam probe to detect silicon, aluminum, calcium, sodium, and carbon. The scanning images showed a clear difference among these elements in their distribution. A large amount of aluminum was found throughout the matrix area, with only a slight concentration gradient, while silicon appeared to be concentrated on the surface of the undissolved glass core. The distribution pattern of calcium was not as clear as that shown by aluminum and silicon. A comparatively higher content of carbon was found closer to the glass surface. These results indicate that aluminum plays an essential role in the setting of the matrix and the surface of the glass dissolved by acrylic acid and changed into the siliceous gel.

[Effects of OK-432 intraportal administration on cell-mediated immune responses].

The effects of OK-432 and/or MMC on host immunity were studied in patients with advanced colorectal cancer. OK-432 was administered to the portal vein, and MMC was dispersed into the peritoneal cavity for prevention of liver metastasis. In the MMC group, NK activity was significantly reduced at 7 days postoperatively, while such a reduction was not seen in the OK and OK + MMC groups. The administration of OK-432 decreased the postoperative proportion of suppressor T cells in the lymphocyte subsets more than that of MMC group. Our results strongly suggest that intraoperative administration of BRM to the patients with advanced colorectal cancer can significantly prevent postoperative immunosuppression.

Effect of "Megafiller" insertion on the wear of composite resins.

We have previously reported that insertion of coarse particles of beta-Quartz Glass Ceramic Insert (Megafiller) into a composite resin markedly reduced the polymerization shrinkage of resin restorative materials. In this study, we examined the effects of Megafiller insertion on wear resistance evaluated by the glass beads abrasion test, and the conventional toothbrushing abrasion test. The depth of wear was determined by measuring the thickness of the specimen before and after the wear tests using a profile projector accurate to 1 micron. In general, the depth of wear of the composites was reduced by Megafiller insertion, but the differences in the depth of wear between composites with and without the Megafiller were not significant except for a few materials. There were slight differences in the wetness of Megafiller in some composite resins.

Nitric oxide mediates the hypertensive response to a modified hemoglobin solution (DCLHb) in rats.

We investigated the effect of nitric oxide synthase inhibition with L-NAME, and L-arginine (nitric oxide synthase substrate), on the hemodynamic response to a modified hemoglobin solution (DCLHb). Rats were given one of the following regimens (all groups hypervolemic except Control): Control-8.0 ml of donor blood (isovolemic exchange); HV-8.0 ml of donor blood; DCLHb-8.0 ml of DCLHb; L-NAME-30 mg.kg-1 of L-NAME followed by 8.0 ml of DCLHb; or L-Arg-8.0 ml of DCLHb followed by L-arginine (600 mg.kg-1). Mean arterial blood pressure (MABP) was continuously recorded and the change compared to baseline and expressed as delta MABP. delta MABP was greater in the HV and DCLHb groups versus the Control and L-NAME groups; and was greater in the DCLHb group versus the HV group. delta MABP was not different between the Control and L-NAME group. In the L-Arg group the initial delta MABP (after DCLHb) was similar to the DCLHb group; however, after L-arginine administration delta MABP was not different from the Control group. This study supports a hypothesis that DCLHb effects an increase in MABP by a nitric oxide related mechanism.

Polymerization shrinkage and contraction force of composite resin restorative inserted with "Megafiller".

This study quantified the contraction force and polymerization shrinkage of composite resins with/without beta-Quartz Glass Ceramic Inserts (BQCI) as "Megafiller". The materials used for the determination included a chemically cured composite and five light-cured composites. The system for measuring contraction force consisted of a transparent teflon tube for preparing the specimen, a small load cell, a dynamic strain gauge and a pen-recorder. After the composite was packed into the teflon mold, a BQCI (Type R3) was inserted through the opening and the specimen was cured. Linear polymerization shrinkage of the composites was measured every 10 seconds from the start of mixing or irradiation to 90 minutes by the mercury bath method. Three pieces each of BQCI (Type T3) were inserted in each specimen. The results suggested that BQCI was markedly effective in reducing polymerization shrinkage, but was not always effective in reducing the contraction force during polymerization.

The clinical pharmacokinetics of two different preparations of intrarectal ketoprofen following spinal or local anesthesia for anal surgery.

Two different preparations of commercially available suppositories containing Ketoprofen (KP) were administered to 49 patients immediately following anal surgery. The KP was prepared as either fatty suppositories (FS) or gelatin capsulated suppositories (GCS) and surgery was performed under either spinal (n = 37) or local anesthesia (n = 12). Similar results were observed in the kinetics of KP after both FS and GCS administration. The extent of bioavailability of the two dosage forms in the patient groups and control subjects (n = 10) were essentially equal. When the pharmacokinetic parameters of KP were compared between patient groups under spinal and local anesthesia, significant differences were found in the values of the peak level (C max), peak time (T max), and terminal phase half-life (t 1/2). The C max decreased by one-half, while the T max and t 1/2 increased twice and four times, respectively, in patient operated on under spinal anesthesia compared to those operated on under local anesthesia. The absorption rate constant (Ka) following spinal anesthesia was significantly less than that following local anesthesia or that of the healthy subjects (p less than 0.01). A "flip-flop" phenomena could be seen in the time profiles of plasma KP concentration following spinal anesthesia.

[Clinical evaluation of ACDEMIN in the field of dentistry].

A clinical trial was performed to examine the effect of ACDEMIN, a combination of lysozyme chloride and vitamins (manufactured by Grelan Pharmaceutical Co., Ltd.,; supplied by Takeda Chemical Industries, Ltd.). The subjects were 65 patients with slight to moderate symptoms associated with locally developed diseases including gingivitis, periodontitis, pericoronitis of the wisdom tooth and gingival abscess. Improvement of the condition was evaluated according to symptom on the basis of local findings examined prior to and 7 days after administration. Adverse effects were also evaluated in terms of discomfort. General improvement was determined on the basis of improvement in symptoms and general safety on the basis of a comprehensive assessment of the adverse effects. The usefulness of the drug was determined on the basis of general improvement and general safety as assessed above. The results were as follows: 1) Of the 65 patients who entered the trial, 62 completed the course of administration. 2) The rates of improvement ("slightly improved" or better) according to symptom were 65.6% for gingival inflammation, 40.0% for bleeding, 50.0% for pus discharge, 41.8% for swelling, 61.9% for local pain, 26.7% for mouth odor, 21.7% for color tone and 62.3% for discomfort. 3) The rates of usefulness ("slightly useful" or better) according to disease were 66.7% for gingivitis, 92.0% for periodontitis, 81.8% for pericoronitis of the wisdom tooth and 100.0% for gingival abscess. 4) The usefulness of the drug was graded "very useful" in 4 patients, "fairly useful" in 18, "slightly useful" in 31 and "not useful" in none, with an overall rate of usefulness of 85.5% ("faily useful" or better). 5) No patients presented symptoms indicating an adverse effect.