Effects of liquefied sake lees on growth performance and faecal and blood characteristics in Japanese Black calves.

Liquefied sake lees, a by-product of Japanese sake, is rich in Saccharomyces cerevisiae, proteins, and prebiotics derived from rice and yeast. Previous studies have reported that Saccharomyces cerevisiae fermentation products improved the health, growth, and faecal characteristics of preweaning calves. This study investigated the effects of adding liquefied sake lees to milk replacer on the growth performance, faecal characteristics, and blood metabolites of preweaning Japanese Black calves from 6 to 90 days of age. Twenty-four Japanese Black calves at 6 days of age were randomly assigned to one of three treatments: No liquefied sake lees (C, n = 8), 100 g/d (on a fresh matter basis) liquefied sake lees mixed with milk replacer (LS, n = 8), and 200 g/d (on a fresh matter basis) liquefied sake lees mixed with milk replacer (HS, n = 8). The intake of milk replacer and calf starter, as well as, the average daily gain did not differ between the treatments. The number of days counted with faecal score 1 in LS was higher than in HS (P < 0.05), while the number of days with diarrhoea medication in LS and C was lower than HS (P < 0.05). The faecal n-butyric acid concentration tended to be higher in LS compared to C (P = 0.060). The alpha diversity index (Chao1) was higher in HS than in C and LS at 90 days of age (P < 0.05). The principal coordinate analysis (PCoA) using weighted UniFrac distance showed that the bacterial community structures in faeces among the treatments at 90 days of age were significantly different (P < 0.05). The plasma ß-hydroxybutyric acid concentration, an indicator of rumen development, was higher for LS than in C throughout the experiment (P < 0.05). These results suggested that adding liquefied sake lees up to 100 g/d (on a fresh matter basis) might promote rumen development in preweaning Japanese Black calves.

Translocator protein 18kDa antagonist ameliorates stress-induced stool abnormality and abdominal pain in rodent stress models.

BACKGROUND: Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder characterized by abdominal pain and abnormal bowel habits, both of which are exacerbated by psychological stress. The translocator protein 18kDa (TSPO) is a marker of reactive gliosis in a number of central nervous system (CNS) diseases and responsible for many cellular functions, including neurosteroidogenesis. Although it has been reported that psychological stress disturbs neurosteroids levels, the pathophysiological relevance of TSPO in IBS is poorly understood. METHODS: We examined the effects of a TSPO antagonist, ONO-2952, on stress-induced stool abnormality and abdominal pain in rats, and on anxiety-related behavior induced by cholecystokinin. KEY RESULTS: Oral administration of ONO-2952 attenuated stress-induced defecation and rectal hyperalgesia in rats with an efficacy equivalent to that of a 5-HT3 receptor antagonist. In addition, ONO-2952 suppressed cholecystokinin-induced anxiety-like behavior with an efficacy equivalent to that of psychotropic drugs. On the other hand, ONO-2952 did not affect spontaneous defecation, gastrointestinal transit, visceral nociceptive threshold, and neurosteroid production in non-stressed rats even at a dose 10 times higher than its effective dose in the stress models. CONCLUSIONS AND INFERENCES: These results suggest that TSPO antagonism results in antistress action, and that ONO-2952 is a promising candidate for IBS without side effects associated with current treatment.

Effects of Soy Phytoestrogens and New Zealand Functional Foods on Bone Health.

New Zealand is a rich source of food components that may have bioactivity on bone. Docosahexaenoic acid (DHA) from fish oil has been shown to maintain bone in ovariectomised (OVX) rats. Kiwifruit, a source of fibre and carotenoids, may also affect bone via a prebiotic as well as direct cell-based mechanisms. We aimed to 1) ascertain the effects of DHA on two cell models, including interactions with soy isoflavones; 2) and investigate the specific effects of carotenoids from kiwifruit as well as whole kiwifruit in cell-based and rodent models as well as in a human study. RAW 264.7 mouse monocytes or mouse bone marrow was used to generate osteoclasts (OC). Cells were exposed to the agents between 5 and 21 d and formation and activity of OC measured, including molecular markers. DHA inhibited OC formation in both cell models, including expression of cathepsin K, NFATc1 as well as actin ring formation. Combination with isoflavones enhanced these effects. In OVX rats and mice fed with kiwifruit for 8 wk, green kiwifruit reduced the rate of bone loss after OVX, and in mice it reduced C-telopeptide of Type 1 collagen (CTX) levels and RANKL expression while in menopausal women, green kiwifruit affected blood lipids and bone markers positively.

Moderate magnesium-restricted diet affects bone formation and bone resorption in rats.

This study investigated the effects of moderate magnesium (Mg)-restricted diet on bone formation and bone resorption in rats. Weanling Wistar strain rats were randomly divided into three dietary groups of 6 rats each and fed their respective diets; a control diet containing 0.05% Mg (C), a half Mg diet containing 0.025% Mg (1/2Mg), or a one-fifth Mg diet containing 0.01% Mg (1/5Mg), for 21 days. Serum osteocalcin level was significantly reduced with decreasing dietary Mg level. Urinary excretion of C-terminal telopeptide of type 1 collagen was significantly higher in the 1/5Mg group than in the C group. Serum insulin-like growth factor-1 (IGF-1) level was significantly lower in the 1/2Mg and 1/5Mg groups than in the C group. Serum soluble receptor activator of nuclear factor-kappaB ligand (sRANKL) level was significantly higher in the 1/2Mg and 1/5Mg groups than in the C group. These results showed that a moderate Mg-restricted diet induced a decrease in bone formation and an increase in bone resorption. Furthermore, these changes of bone formation and bone resorption might be caused by serum IGF-1 and sRANKL levels, respectively.

Onset of nephrocalcinosis depends on dietary phosphorus concentration in male rats fed a magnesium-deficient diet.

Although a magnesium (Mg)-deficient diet is generally known to induce nephrocalcinosis, our previous study observed that despite the administration of a Mg-deficient diet, the kidney calcium (Ca) and phosphorus (P) concentrations were not increased in male rats. We speculated that this result was due to the P concentration of the experimental diet based on the AIN-93G formula used in the previous study. In the present study, male rats were fed modified AIN-93G diets containing the two different Mg concentrations [0.5 g per kg diet (normal-Mg) or Mg-free (Mg-deficient)] and three different P concentrations [3 (3-P), 5 (5-P) or 7 (7-P) g per kg diet]. By histological examination of the kidney, nephrocalcinosis was not observed in rats fed on the Mg-deficient diet containing 3-P While nephrocalcinosis appeared in rats fed on the Mg-deficient diet containing 5-P and 7-P The degree of nephrocalcinosis was severe in rats fed on the Mg-deficient diet containing 7-P compared with rats fed on the Mg-deficient diet containing 5-P These results demonstrated that the Mg-deficient diet based on AIN-93G formula dose not induce nephrocalcinosis and that the Mg-deficient diet based on AIN-93G formula with increased dietary P concentrations induces nephrocalcinosis in male rats. We suggest that the onset of nephrocalcinosis could depend on the dietary P concentration in male rats fed on a Mg-deficient diet.

Effect of dietary magnesium supplementation on bone loss in rats fed a high phosphorus diet.

The purpose of this study was to investigate the effect of dietary magnesium (Mg) supplementation on bone loss in rats fed a high phosphorus (P) diet. Weanling Wistar strain rats were randomly divided into four dietary groups of 6 rats each and fed their respective diets; a diet containing 0.3% P and 0.05% Mg (C), a diet containing 1.5% P and 0.05% Mg (HP), a diet containing 0.3% P and 0.15% Mg (HMg), or a diet containing 1.5% P and 0.15% Mg (HPMg), for 21 days. Compared to the C and HMg groups, serum parathyroid hormone (PTH) concentration was significantly higher in the HP and HPMg groups. Serum osteocalcin concentration and urinary excretion of C-terminal telopeptides of type I collagen (CTx), markers of bone turnover, were significantly higher in the HP and HPMg groups than in the C and HMg groups. Dietary Mg supplementation had no significant effects on serum PTH and osteocalcin concentrations, while urinary excretion of CTx was significantly lower in the HPMg group than in the HP group. These results suggested that dietary Mg supplementation suppressed bone resorption due to high P diet.

Effects of high calcium intake on bone metabolism in magnesium-deficient rats.

We examined the effects of high calcium (Ca) intake on bone metabolism in magnesium (Mg)-deficient rats. Male Wistar rats were divided into three groups, with each group having a similar mean body weight, and fed a control diet (control group), a Mg-deficient diet (Mg-deficient group) or a Mg-deficient Ca-supplemented diet (Mg-deficient Ca-supplemented group) for 14 d. Femoral Ca content was significantly lower in the Mg-deficient Ca-supplemented group than in the control group and Mg-deficient group. Femoral Mg content was significantly lower in the Mg-deficient group and Mg-deficient Ca-supplemented group than in the control group. Furthermore, femoral Mg content was significantly lower in the Mg-deficient Ca-supplemented group than in the Mg-deficient group. Serum osteocalcin levels (a biochemical marker of bone formation) were significantly lower in the two Mg-deficient groups than in the control group. As a biochemical marker of bone resorption, urinary deoxypyridinoline excretion was significantly higher in the Mg-deficient Ca-supplemented group than in the control group and Mg-deficient group. The results in the present study suggest that high Ca intake had no preventive effect on alteration of bone metabolism in Mg-deficient rats.

Arundic acid (ONO-2506) ameliorates delayed ischemic brain damage by preventing astrocytic overproduction of S100B.

After focal cerebral ischemia, the infarct volume increases rapidly within acute infarct expansion (initial 12 to 24 h) and continues slowly during delayed infarct expansion (25 to 168 h). While acute infarct expansion represents progressive necrosis within the ischemic core, delayed infarct expansion starts as disseminated apoptotic cell death in a narrow rim surrounding the infarct border, which gradually coalesces to form a larger infarct. Discovery of a distinct correlation between reactive astrogliosis along the infarct border and delayed infarct expansion in the rodent ischemia model led us to investigate the possible causal relationship between the two events. Specifically, the calcium binding protein S100B exerts detrimental effects on cell survival through activation of various intracellular signaling pathways, resulting in altered protein expression. Arundic acid [(R)-(-)-2-propyloctanoic acid, ONO-2506] is a novel agent that inhibits S100B synthesis in cultured astrocytes. In the rodent ischemia model, this agent was shown to inhibit both the astrocytic overexpression of S100B and the subsequent activation of signaling pathways in the peri-infarct area. Concurrently, delayed infarct expansion was prevented, and neurologic deficits were promptly ameliorated. The results of subsequent studies suggest that the efficacy of arundic acid is mediated by restoring the activity of astroglial glutamate transporters via enhanced genetic expression.

Changes in coagulation-fibrinolysis marker and neutrophil elastase following the use of tourniquet during total knee arthroplasty and the influence of neutrophil elastase on thromboembolism.

BACKGROUND: To clarify in detail the mechanism underlying the development and exacerbation of deep venous thrombosis (DVT) and/or pulmonary thromboembolism (PTE), we focused on the following factors: the thrombin-antithrombin III complex (TAT), D-dimer and neutrophil elastase (NE). We basically investigated whether NE played an important role in the development of PTE I a mice model. METHODS: Nineteen rheumatoid arthritis (RA) and six osteoarthritis (OA) patients underwent total knee arthroplasty (TKA) with tourniquet, and 13 RA and 12 OA patients underwent TKA without tourniquet in each group. The blood levels of TAT, D-dimer and NE were measured before surgery, immediately after and during the days following surgery. For the induction of experimental PTE due to coagulation of platelets, adenosine diphosphate (ADP) was administrated, and human NE with ADP was also administrated for the development of DVT and/or PTE. RESULTS: The rates of increase in the mean TAT, D-dimer and NE levels in the group with tourniquet were statistically higher than those in the group without tourniquet after surgery. The mortality of the mouse due to PTE increased from 43 to 67% following ADP and human NE administration compared to a single ADP administration. Histological changes of the lungs in the mice receiving NE and ADP injections were characterized by a diffuse and extensive accumulation of platelets and fibrin in alveolar capillaries and other microvessels. CONCLUSION: We suggest that during TKA, the use of tourniquet induces local release of a large amount of NE from neutrophils, inducing the development of DVT and/or PTE and their exacerbation.

Viewing of complex molecules of ethidium bromide and plasmid DNA in solution by atomic force microscopy.

Tertiary structure changes in plasmid DNA, induced by ethidium bromide intercalation, have been observed in aqueous solutions by the use of an atomic force microscope. A relaxed closed circular pBR322 molecule became a positively supercoiled complex on the drug binding. The supercoiling always resulted in an interwound (or a plectonemic) form, but never a solenoidal (or a toroidal) form. A quantitative analysis of the compactness of such supercoiled complexes has been carried out.

[Immunosuppressive treatment of ulcerative colitis].

5-aminosalicylic compounds and corticosteroids are standard drugs, which have been used for treatment of ulcerative colitis (UC). Although unusually we experience severe active UC, such as refractory cases to these drugs. Immunosuppressive agents are introduced and effective for these cases. In the treatment for UC, 6-mercaptopurine and azathioprine are effective, but it takes a few months until their optimum effect. So these drugs are not suitable for severe active UC which needs rapid treatment. On the other hand, newer immunosuppressive agents such as cyclosporin, tacrolimus have a rapid onset of action. These drugs are very effective, but have side effects. We will review immunosuppressive treatment strategy of UC.

Sequence analysis of alleles at a microsatellite locus D14S299 (wg1c5) and population genetic comparisons.

In order to increase the discriminating power of DNA analysis in personal identification, we evaluated the forensic utility of the microsatellite locus D14S299 (wg1c5) in the Japanese population and also in the Chinese and Caucasian populations. Twelve different alleles were identified in length by gel electrophoresis with silver staining. The major alleles in Japanese were sequenced and designated as the numbers of the variable repeats (GGAT or GGAA). There were five variable regions and extensive homoplasy was found. However, the allele fragment lengths were in 4 bp increments and no "interalleles" were found. The estimated heterozygosity and the polymorphism information content (PIC) were 0.726 and 0.689, respectively in Japanese. Those in Chinese (0.743 and 0.704) were similar to those in Japanese, while those in Caucasians (0.812 and 0.781) were much higher. After adjacent alleles were combined to yield at least five entries, statistical analysis was performed. The power of discrimination (PD) was 0.887 in Japanese, 0.895 in Chinese and 0.935 in Caucasians and no significant deviations from the Hardy-Weinberg equilibrium were found in the three populations. We retyped all apparently homozygous samples using an alternative pair of flanking primers and found them to be true homozygotes. D14S299 appears to be a useful STR locus for forensic practice.

A sudden death from the rupture of a small intestine firstly suspected of acute pancreatitis.

A 51-year-old drunken male was carried to a hospital with acute abdominal pain and was suspected of acute pancreatitis. The patient was treated with fasting, electrolyte transfusion, and anodyne, but took a sudden turn for the worse and died in 16 hours. In the judicial autopsy, rupture of a small intestine was detected. As the police investigated, he had been kicked in the abdomen by an assailant before coming to the hospital. The cause of death was diagnosed to be acute peritonitis due to the rupture of a small intestine. Several problems were pointed out on medical examinations and treatments of this case.

A case of spontaneous femoral neck fracture associated with multicentric reticulohistiocytosis: oversecretion of interleukin-1beta, interleukin-6, and tumor necrosis factor alpha by affected synovial cells.

We describe a case of left femoral neck fracture associated with multicentric reticulohistiocytosis (MR). Biopsy specimens from a skin nodule and from synovial tissue showed histiocytic multinucleated giant cells (MR cells) that are characteristic of MR. A surgical specimen from the resected femoral head revealed that multinucleated giant cells and mononuclear cells invaded the marginal subchondral bone, without evident pannus. These cells also infiltrated into the fracture site, with bone resorption by activated osteoclasts. Immunohistochemical studies of synovium from the left hip joint showed positive staining for interleukin-1beta (IL-1beta), IL-6, and tumor necrosis factor alpha, and abundant cytokine production by cultured synovial cells was demonstrated. These findings suggest that the subchondral invasion and intramedullary infiltration by MR cells caused articular destruction and/or fracture as a result of oversecretion of the cytokines.

A single residue, Lys108, of the delta-opioid receptor prevents the mu-opioid-selective ligand [D-Ala2,N-MePhe4,Gly-ol5]enkephalin from binding to the delta-opioid receptor.

Previously, we found that replacement of the region around the first extracellular loop of the delta-opioid receptor (OPR) with the corresponding region of the mu-OPR gives the high affinity for [D-Ala2,N-MePhe4,Gly-ol5]enkephalin (DAMGO), a mu-opioid-selective ligand, to the resultant chimeric receptor, DMDD, suggesting that the difference in the amino acid sequence within this region between the mu- and delta-OPRs is critical for the discrimination between these receptors by DAMGO. In the current study, we carried out systematic replacements of seven non-conserved residues in this region of the delta-OPR with the corresponding amino acid found in the mu-OPR. Among the seven mutant receptors, only one mutant receptor, delta K108N, showed high affinity (Ki = 18.68 +/- 5.27 nM) for DAMGO, which was comparable to that of the DMDD receptor (Ki = 23.77 +/- 4.27 nM) and 75-fold higher than that of the wild-type delta-OPR (Ki = 1405 +/- 161 nM). Lys108 in the delta-OPR was systematically replaced with 19 kinds of amino acids other than lysine. Among the resultant mutant receptors, 14 mutants bound DAMGO with Ki values comparable to those of the DMDD receptor, ranging from 4.20 to 43.38 nM. These findings suggest that Lys108 of the delta-OPR prevents DAMGO from binding to the delta-OPR rather than that the asparagine residue at the corresponding position in the mu-OPR is necessary for DAMGO binding. In addition, the replacement of Lys108 of the delta-OPR with asparagine dramatically increased the affinity for other peptidic mu receptor-selective ligands, such as dermorphin and D-Pen-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2.

Pharmacological characterization of KT-90 using cloned mu-, delta- and kappa-opioid receptors.

We analyzed the pharmacological characteristics of (-)-3-acetyl-6 beta-acetylthio-N-cyclopropylmethyl-normorphine (KT-90) using Chinese hamster ovary (CHO) cells expressing cloned rat mu-, delta- and kappa-opioid receptors. KT-90 displaced the specific binding of the following radiolabeled ligands selective to the mu-, delta- and kappa-opioid receptors, [3H][D-Ala2,MePhe4,Gly(ol)5]enkephalin (DAMGO), [3H][D-Pen2,D-Pen5]enkephalin (DPDPE), [3H] (+)-(5 alpha, 7 alpha, 8 beta)-N-methyl-N-[7-(1-pyrrolidinyl) l-oxaspiro-(4,5)dec-8-yl]benzeneacetamide (U69,593), with Ki values of 3.3 +/- 0.7, 22.8 +/- 1.5 and 1.9 +/- 0.3 nM, respectively In CHO cells expressing the mu-, delta- and kappa-opioid receptors, KT-90 inhibited forskolin (10 microM)-induced cyclic AMP accumulation in a concentration-dependent manner with IC50 values of 2337 +/- 750, 17.3 +/- 4.6 and 2.0 +/- 0.1 nM, respectively. The maximal inhibitory effects of KT-90 in the cells expressing mu-, delta- and kappa-opioid receptors were significantly lower than those of the type-selective agonists DAMGO, DPDPE and U69,593, respectively. These results indicated that KT-90 acts as a partial agonist on mu-, delta- and kappa-opioid receptors. KT-90 (10 and 100 nM), when added with morphine, produced a rightward shift of the concentration-response curve of morphine to inhibit the cyclic AMP accumulation in CHO cells expressing mu-, but not delta- or kappa-, opioid receptors. This finding is consistent with the findings that lower doses of KT-90 antagonize morphine analgesia in vivo.

Pharmacological study of dihydroetorphine in cloned mu-, delta- and kappa-opioid receptors.

We investigated the binding characteristics of dihydroetorphine, 7,8-dihydro-7 alpha-[1-(R)-hydroxy-1-methylbutyl]-6, 14-endoethanotetrahydro-oripavine, and its effect on the inhibitory system of cyclic AMP production using cloned mu-, delta- and kappa-opioid receptors expressed on Chinese hamster ovary cells. The Ki values of dihydroetorphine for the mu-, delta- and kappa-opioid receptors were 4.5 x 10(-10). 1.8 x 10(-9) and 5.7 x 10(-10) M, respectively. On the other hand, those of morphine were 1.9 x 10(-9), 1.4 x 10(-6) and 1.3 x 10(-7) M, respectively. Through all of these three types of opioid receptors, dihydroetorphine inhibited forskolin (10 microM)-stimulated cyclic AMP production via pertussis toxin-sensitive G protein(s), and the inhibitory effects were antagonized by co-application with opioid receptor antagonists. The IC50 values of dihydroetorphine for the inhibition of cyclic AMP production through the mu-, delta- and kappa-opioid receptors were 4.2 x 10(-11), 8.6 x 10(-10) and 4.3 x 10(-9) M. respectively. On the other hand, those of morphine were 2.6 x 10(-8), 2.6 x 10(-6) and 1.9 x 10(-6) M, respectively. These results indicate that dihydroetorphine, unlike morphine which preferentially binds the mu-opioid receptor, binds not only mu- but also delta- and kappa-opioid receptors with high affinity and acts as a more potent agonist than morphine for all of the three types of receptors.

Suppression of naloxone-precipitated withdrawal jumps in morphine-dependent mice by stimulation of prostaglandin EP3 receptor.

1. We have shown that intracisternal (i.c.) administration of interleukin-1 beta (IL-1 beta) attenuates naloxone-precipitated withdrawal jumps in morphine-dependent mice, and the effect was partly mediated by the corticotropin-releasing factor. To elucidate further other possible mechanisms involved in the inhibitory effect of IL-1 beta on morphine withdrawal jumping behaviour, in this study, we examined the involvement of the prostaglandin-synthesis pathway, because prostaglandins have been shown to mediate the several central effects of IL-1. Furthermore, we examined the effects of subtype-selective prostaglandin receptor agonists on morphine withdrawal jumping behaviour. 2. Mice were rendered morphine-dependent by subcutaneous implantation of a pellet containing 11.5 +/- 0.3 mg morphine hydrochloride for 48 h. Morphine withdrawal syndromes were precipitated by intraperitoneal (i.p.) injection of naloxone (10 mg kg-1). The degree of physical dependence on morphine was estimated by counting the number of jumps, one of the typical withdrawal signs in mice, for 40 min. 3. The inhibitory effect of IL-1 beta (1 ng/mouse) administered intracisternally 30 min before naloxone (10 mg kg-1, i.p.) was significantly blocked by pretreatment with sodium salicylate (a cyclo-oxygenase inhibitor, 10 ng or 30 ng/mouse) administered intracisternally 15 min before IL-1 beta, while i.c. administration of sodium salicylate alone (3 ng, 10 ng or 30 ng/mouse) followed by i.c. administration of vehicle instead of IL-1 beta did not significantly change the number of jumps precipitated by naloxone. 4. Intracisternal administration of M&B28,767 (an EP3-receptor agonist, 1 fg-30 ng/mouse) and sulprostone (an EP1/EP3-receptor agonist, 10 fg-100 ng/mouse) 30 min before naloxone (10 mg kg,-1 i.p.) attenuated withdrawal jumps with a U-shaped dose-response, reaching a peak at 10 pg/mouse and 100 pg/mouse, respectively. On the other hand, i.c. administration of iloprost (an EP1/IP-receptor agonist, 10 fg-100 ng/mouse), butaprost (an EP2-receptor agonist, 10 fg-100 ng/mouse) or prostaglandin F2 alpha (a FP-receptor agonist, 10 fg-100 ng/mouse) 30 min before naloxone (10 mg kg-1, i.p.) did not significantly change the number of jumps precipitated by naloxone. 5. These results indicate that the prostaglandin-synthesis pathway is, at least in part, involved in the inhibitory effect of IL-1 beta on naloxone-precipitated withdrawal jumps in morphine-dependent mice, and that the prostaglandin synthesized in the brain suppresses the morphine withdrawal jumping behaviour via the EP3-receptor, but not via the EP1-, EP2-, IP- or FP-receptor.

DAMGO, a mu-opioid receptor selective ligand, distinguishes between mu-and kappa-opioid receptors at a different region from that for the distinction between mu- and delta-opioid receptors.

The structural basis of opioid receptors (OPRs) for the subtype-selective binding of DAMGO, a mu-opioid receptor selective ligand, was investigated using chimeric mu/kappa-OPRs. Replacement of the region from the middle of the fifth transmembrane domain to the C-terminal of mu-OPR with the corresponding region of mu-OPR remarkably decreased the binding affinity to DAMGO, while the reciprocal chimera revealed the high affinity to DAMGO. These results indicate that DAMGO distinguishes between mu- and mu-OPRs at the region around the third extracellular loop, different from the case of the distinction between mu-and delta-OPRs in which the region around the first extracellular loop is important. Furthermore, displacement studies revealed that the region around the third extracellular loop is involved in the discrimination between mu- and kappa-OPRs not only by peptidic mu- selective ligands but also by non-peptidic ligands, such as morphine and naloxone.

Intracisternal administration of interleukin-1 beta attenuates naloxone-precipitated withdrawal in morphine-dependent mice.

The effect of central administration of interleukin-1 beta on naloxone-precipitated withdrawal in morphine-dependent mice was studied. The degree of physical dependence on morphine was estimated by counting the number of jumps precipitated by naloxone, one of the typical withdrawal signs. Intracisternal (i.c.) administration of interleukin-1 beta (0.01-1 ng/5 microliters per mouse) to morphine-dependent mice 30 min prior to the injection of naloxone (10 mg/kg i.p.) decreased the number of jumps in a dose-dependent manner. The effect of interleukin-1 beta (1 ng) was significantly antagonized when it was co-administered with interleukin-1 receptor antagonist (1 microgram/mouse). These results suggest that centrally administered interleukin-1 beta could attenuate naloxone-precipitated withdrawal in morphine-dependent mice via interleukin-1 receptors in the brain. Co-administration of alpha-melanocyte-stimulating hormone (300 ng/mouse) or alpha-helical corticotropin-releasing factor (CRF)-(9-41), a CRF receptor antagonist (300 ng/mouse), with interleukin-1 beta also antagonized the inhibitory effect of interleukin-1 beta (1 ng). Moreover, i.c. administration of CRF (200 ng/mouse) significantly decreased the number of jumps.