Search

It is established that neuropeptide Y (NPY) is a transmitter of parasympathetic secretory impulses in submandibular gland. The neuropeptides substance P, vasoactive intestinal peptide (VIP) and calcitonin gene-related peptide (CGRP) are likely mediators of secretory parasympathetic responses of the gland. Previously, we have shown that substance P, VIP and CGRP modulate voltage-dependent Ca(2+) channels (VDCCs) in hamster submandibular ganglion (SMG) neurons. In this study, we attempt to characterize the effect of NPY on VDCCs current using Ba(2+) (I(Ba)) in SMG neurons. Application of NPY caused both facilitation and inhibition of L-type and N/P/Q-type I(Ba), respectively. Intracellular dialysis of the Gα(s)-protein antibody attenuated the NPY-induced facilitation of I(Ba). The adenylate cyclase (AC) inhibitor, as well as protein kinase A (PKA) inhibitor attenuated the NPY-induced facilitation of I(Ba). Intracellular dialysis of the Gα(i)-protein antibody attenuated the NPY-induced inhibition of I(Ba). Application of a strong depolarizing voltage prepulse attenuated the NPY-induced inhibition of I(Ba). These results indicate that NPY facilitates L-type VDCCs via Gα(s)-protein involving AC and PKA. On the other hand, NPY also inhibits N/P/Q-type VDCCs via Gα(i)-protein βγ subunits in the SMG neurons., (Copyright © 2012 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.)

Bradykinin (BK) is involved in bone resorption in chronic inflammatory diseases. During bone formation, 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) plays an important role in the regulation of Ca2+. In osteoblasts, 1,25(OH)2D3 stimulates transmembrane influx of Ca2+ through voltage-sensitive Ca2+ channels (VSCCs). Voltage sensitive Ca2+ channels serve as crucial mediators of membrane excitability and many Ca2+-dependent functions, including bone growth, regulation of proliferation, enzyme activity and gene expression. The purpose of this study was to investigate the effects of BK and 1,25(OH)2D3 on VSCC currents carried by Ba2+ (IBa). Application of 1,25(OH)2D3 facilitated IBa in a voltage-dependent manner. Pretreatment with SQ22536 (an adenylate cyclase inhibitor) attenuated 1,25(OH)2D3-induced facilitation of IBa. Bradykinin and BK1 receptor agonist [Lys-des-Arg9]-BK also facilitated IBa. After 24 h or 7 days exposure to BK, that is, under chronic inflammatory conditions, application of 1,25(OH)2D3 inhibited IBa. In addition, pretreatment with PD98,059, a mitogen-activated protein kinase (MAPK) tyrosine kinase inhibitor, attenuated 1,25(OH)2D3-induced inhibition of IBa. These results indicate that, under normal conditions, 1,25(OH)2D3 acts with adenylate cyclase to facilitate VSCCs, whereas under chronic inflammatory conditions it acts with MAPK to inhibit VSCCs in pre-osteoblasts., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

The interaction between proteins and ligands was evaluated by T7 RNA polymerase transcription with a DNA-modified ligand. The principle of this method is suppression of T7 RNA polymerase transcription by binding of a protein to small ligand modified by conjugation with a T7 RNA polymerase promoter. To demonstrate proof of principle, biotin or antifolate methotrexate was modified by covalent attachment of a T7 RNA promoter. Using these T7 RNA promoter-modified ligands, T7 RNA polymerase transcriptions were performed in the presence or absence of an anti-biotin antibody or recombinant human dihydrofolate reductase, respectively. Transcription was suppressed in the presence of each binding protein plus its modified ligand, but not in the absence of the binding protein., (Copyright 2010 Elsevier Inc. All rights reserved.)

Resistance passage studies were conducted with five INIs (integrase inhibitors) that have been tested in clinical trials to date: a new naphthyridinone-type INI S/GSK-364735, raltegravir, elvitegravir, L-870,810 and S-1360. In establishing the passage system and starting from concentrations several fold above the EC(50) value, resistance mutations against S-1360 and related diketoacid-type compounds could be isolated from infected MT-2 cell cultures from day 14 to 28. Q148R and F121Y were the two main pathways of resistance to S/GSK-364735. Q148R/K and N155H, which were found in patients failing raltegravir treatment in Phase IIb studies, were observed during passage with raltegravir with this method. The fold resistance of 40 mutant molecular clones versus wild type virus was compared with these five INIs. The overall resistance pattern of S/GSK-364735 was similar to that of raltegravir and other INIs. However, different fold resistances of particular mutations were noted among different INIs, reflecting a potential to develop INIs with distinctly different resistant profiles.

Objective: To determine to what extent tonic contraction of the testing muscle modulates the effect of remote muscle contraction on motor evoked potentials (MEPs) and cortical silent periods (CSPs) in resting and active proximal and distal muscles following transcranial magnetic stimulation (TMS). In addition, we tested whether the remote effect on MEP was observable when the test MEP was small., Methods: While performing tonic abductions of the first dorsal interosseous (FDI), flexor carpi radialis, or anterior deltoid muscles, subjects made phasic dorsiflexions of the right ankle at various forces. MEPs and CSPs were induced by separately optimized TMS intensities and locations in the left motor cortex and recorded electromyographically., Results: Phasic dorsiflexion increased MEP amplitude and shortened CSP duration in a dorsiflexion intensity-dependent manner in all muscles tested. At test MEPs <10% of Mmax, remote effects on MEP amplitude and CSP duration were significantly attenuated while the testing muscle was active., Conclusions: Phasic contraction of remote muscles potentiates excitatory- and suppresses inhibitory intracortical neuronal pathways converging on corticospinal tract cells innervating the upper limb muscles even when they are active. However, the magnitude of the remote effect on MEP amplitude strongly depends on the test MEP amplitude., Significance: Although remote effects on MEP amplitude and CSP duration are observed even when the test muscle is active, the magnitude of the remote effect strongly depends on TMS intensity.

Objective: We investigated to what extent intralimb and interlimb cutaneous reflexes are altered while simultaneously performing arm and leg cycling (AL cycling) under different kinematic and postural conditions., Methods: Eleven subjects performed AL cycling under conditions in which the arm and leg crank ipsilateral to the stimulation side were moved synchronously (in-phase cycling) or asynchronously (anti-phase cycling) while sitting or standing. Cutaneous reflexes following superficial radial or superficial peroneal nerve stimulation (2.0-2.5 times radiating threshold, 5 pulses at 333 Hz) were recorded at 4 different pedal positions from 12 muscles in the upper and lower limbs. Cutaneous reflexes with a peak latency of 80-120 ms were then analyzed., Results: The magnitude of interlimb and intralimb cutaneous reflexes in the arm and leg muscles was significantly modulated depending on the crank position for the relevant limb (phase-dependent modulation). A significant correlation between the magnitude of the cutaneous reflex and background EMG was observed in the majority of muscles during static contraction, but not during AL cycling (task-dependent modulation). No significant difference was found in comparisons of the magnitude of intralimb and interlimb cutaneous reflexes obtained during in- and anti-phase AL cycling. Qualitatively, the same results were obtained during AL cycling while sitting or standing. In addition, the modulation of cutaneous reflexes in arm muscles was identical among in-phase, anti-phase and isolated arm cycling. Results were the same for leg muscles., Conclusions: Cutaneous reflexes in arm muscles are little influenced by rhythmic movement of the legs and vice versa during AL cycling. It is likely that neural components that control interlimb reflexes are loosely coupled during AL cycling while sitting or standing., Significance: Our results provide a better understanding of the coordination between the upper and lower limbs during rhythmic movement.

Objective: The current study was designed to determine location-specificity in long latency cutaneous reflexes in intrinsic human hand muscles while performing a simple abduction and a manual task., Methods: Subjects comprised of 13 neurologically intact healthy volunteers. Cutaneous reflexes following non-noxious electrical stimulation to the digits of the hand (digit 1, D1; digit 2, D2; and digit 5, D5) were elicited while the subjects performed isolated isometric contraction of the abductor pollicis brevis (APB), first dorsal interosseous (FDI) and abductor digiti minimi muscles (ADM). The cutaneous reflexes were also elicited while the subjects performed a pincer grip with D1 and D2 while slightly lifting the hand from the supporting surface by abduction of D5 (manual task)., Results: While performing isolated tonic voluntary contraction of the APB, FDI and ADM, the magnitude of E2 (peak latency approximately 60-90 ms) was larger when stimulation was delivered to the homotopic digit (e.g. APB response following D1 stimulation) than to the heterotopic nearby (e.g. APB response following D2 stimulation) or heterotopic distant digit (e.g. APB response following D5 stimulation). I2 ( approximately 90-120 ms) and E3 ( approximately 120-180 ms) were significantly larger following D5 stimulation than D1 or D2 stimulation in all muscles tested. The size of each component in the ADM following D1 and D2 stimulation did not increase even when the contraction level of the ADM increased. However, while performing the manual task, the E2 response in the ADM following both D1 and D2 stimulation was significantly increased as compared to that recorded during isolated D5 abduction., Conclusions: Long latency cutaneous reflexes following non-noxious electrical stimulation are organized in a highly location-specific as well as task-dependent manner., Significance: Our findings provide further insight into the nature and functional significance of long latency cutaneous reflexes in human intrinsic hand muscles.

Whole-cell patch-clamp recordings were performed on freshly dissociated nucleus tractus solitarius (NTS) of rat to determine the action of extracellular adenosine 5'-triphosphate (ATP) and adenosine (ADO) on voltage-dependent calcium channel (VDCC) currents (I(Ca)). Application of ATP and ATP-analog inhibited I(Ca). The rank order of potency of inhibition of I(Ca) was 2-methylthioATP (2-MeSATP) > ATP > adenosine 5'-diphosphate (ADP) >> alpha,beta-methylene ATP (alpha,beta-MeATP) = uridine 5'-triphosphate (UTP). Application of ADO receptor agonists also inhibited I(Ca). The rank order of potency of inhibition of I(Ca) was N(6)-cyclohexyladenosine (CHA) > ADO > 2-(4-(2-carboxyethyl)phenylethylamino)adenosine-5'-N-ethylcarboxamideadenosine (CGS-21680) > N(6)-2-(4-aminophenyl)ethyladenosine (APNEA). Application of prepulse attenuated these inhibition. Both intracellular dialysis of guanosin 5'-O-(2-thiodiphosphate) (GDP-beta-S) and anti-G(i) antibody also attenuated these inhibition. L-, N- and P/Q-type VDCCs were inhibited by ATP. In contrast, N- and P/Q-type VDCCs were inhibited by ADO. In addition to inhibition, application of 100 microM ATP facilitated I(Ca). Intracellular dialysis of GDP-beta-S did not attenuate these facilitations. In conclusion, activation of P2Y purinoceptors inhibits L-, N- and P/Q-types VDCCs via G(i)-protein betagamma subunits. Activation of A(1) and/or A(2) receptors inhibit N- and P/Q-types VDCCs via G(i)-protein betagamma subunits. Activation of P2X purinoceptors facilitates Ca(2+) entry in NTS.

The inhibitory effects of kappa-opioid receptor agonists on systemic skin scratching induced by the intravenous administration of morphine, a micro-opioid receptor agonist, were investigated in rhesus monkeys. Intravenous pretreatment with kappa-opioid receptor agonists, either TRK-820 at 0.25 and 0.5 microg/kg or U-50488H at 64 and 128 microg/kg, inhibited systemic skin scratching induced by morphine at 1 mg/kg, i.v. in a dose-dependent manner. By the intragastric route, apparent inhibitory effects on morphine-induced systemic skin scratching were evident following pretreatment with TRK-820 at 4 microg/kg but not with U-50488H from 512 to 2048 microg/kg. These results suggest that TRK-820 produces antipruritic effects on i.v. morphine-induced systemic skin scratching and is more readily absorbed intragastrically than is U-50488H, resulting in high bioavailability in the intragastric route.

The Vasoactive intestinal polypeptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) are two novel neuropeptides which produce particular biological effects caused by interaction with G-protein-coupled receptors. We have shown in a previous study where VIP and PACAP 38 inhibit voltage-dependent calcium channel (VDCC) currents (ICa) via G-proteins in hamster submandibular ganglion (SMG) neurons. In this study, we attempt to further characterize the signal transduction pathways of VIP-and PACAP 38-induced modulation of ICa. Application of 1 microM VIP and PACAP 38 inhibited ICa by 33.0 +/- 3.1% and 36.8 +/- 2.6%, respectively (mean +/- S.E.M., n = 8). Application of strong voltage prepulse attenuated PACAP 38-induced inhibition of ICa. Pretreatment of cAMP dependent protein kinase (PKA) activator attenuated VIP-induced inhibition, but not the PACAP 38-induced inhibition. Intracellular dialysis of the PKA inhibitor attenuated the VIP-induced inhibition, but not the PACAP 38-induced inhibition. Pretreatment of protein kinase C (PKC) activator and inhibitor attenuated VIP-induced inhibition, but not the PACAP 38-induced inhibition. Pretreatment of cholera toxin (CTX) attenuated PACAP 38-induced inhibition of ICa. These findings indicate that there are multiple signaling pathways in VIP and PACAP 38-induced inhibitions of ICa: one pathway would be the VPAC1/VPAC2 receptors-induced inhibition involving both the PKA and PKC, and another one concerns the PAC1 receptor-induced inhibition via Gs-protein betagamma subunits. The VIP-and PACAP 38-induced facilitation of ICa can be observed in the SMG neurons in addition to inhibiting of ICa., (Copyright 2004 Elsevier B.V.)

Angiotensin II (AngII) is one of the most important vasoconstrictive hormones but is also known to act as a neuromodulator and a neurotransmitter in the central and peripheral nervous systems. In a previous study, we have shown that AngII, mediated by AT(1) receptors, inhibits voltage-dependent calcium channel (VDCC) currents (I(Ca)) via G-proteins in submandibular ganglion (SMG) neurons. In this study, we further characterized the signal transduction of AngII-induced inhibition of I(Ca). Application of 1 microM AngII inhibited I(Ca) by 32.1+/-2.7% (mean+/-S.E.M., n=9). Intracellular dialysis of anti-G(q/11) antibodies attenuated these inhibition (8.8+/-1.3%, n=6). In addition, treatment of protein kinase C (PKC) activator and inhibitor also attenuated these inhibition (8.0+/-0.9 and 9.8+/-0.9%, n=6 and 9, respectively). We therefore conclude that AngII inhibits VDCC via G(q/11)-proteins involving in SMG neurons. In addition, such PKC-dependent pathways mediated mainly L-type VDCC inhibition.

Charcot joint is a disease that often occurs in patients with diabetes mellitus, tabes dorsalis, syringomyelia, chronic alcoholism, leprosy, trauma, or infection after fractures and dislocations. The treatment for Charcot joint has various complications, such as skin lesions, infections, and delayed union. We present our experience with a male patient who developed Charcot joint-like changes without diabetes mellitus or any other disease after an ankle fracture due to minor trauma.

Angiotensin II (Ang II) is one of the most important vasoconstrictive hormones but is also known to act as a neuromodulator and a neurotransmitter in the central and peripheral nervous systems. In a previous study, we have shown that Ang II, via AT1 receptors, induced depolarization by inhibition of M-type K(+) channels and SK channels in submandibular ganglion (SMG) neurons. In this study, we investigated the effects of Ang II on calcium channel current (I(Ca)) in acutely dissociated SMG neurons by the patch-clamp technique using the whole-cell configuration. Ang II inhibited total I(Ca) by 32.1+/-2.7%. The half-maximum inhibitory concentration (IC(50)) of Ang II for inhibiting I(Ca) was 0.8 microM. In the presence of 1 microM losartan, which is a selective antagonist of AT1 receptors, the effect of Ang II was attenuated (7.6+/-1.5%). Application of a strong depolarizing voltage prepulse did not affect the Ang II-induced inhibition of I(Ca) (32.8+/-2.8%). Intracellular dialysis of GDP-beta-S attenuated the inhibition of I(Ca) (6.8+/-2.1%). The mean percentage inhibitions of L-, N- and P/Q-type VDCCs by Ang II were 29.1+/-1.7, 16.3+/-6.0 and 1.2+/-0.8%, respectively, of the total I(Ca).

Introduction: A sensitive and simple enzymatic cycling method is described for the quantitation of myo-inositol in biological samples., Methods: The method involves the use of a sensitive and simple enzymatic cycling method is described for the quantitation of myo-inositol in biological samples. The method involves use of thio-NAD(+), NADH and thermostable myo-inositol dehydrogenase (IDH; EC. 1.1.1.18) and measurement of the increase in absorbance at 405 nm of thio-NADH at 37 degrees C., Results: The calibration curve for myo-inositol was linear (r=1.00) between 10 and 400 micromol/l. Analytical recoveries of exogenous myo-inositol added to serum and urine were 100-105% and 98-103%, respectively. Within-run and between-run coefficient of variation (CV) were 0.6-2.1% and 1.1-3.0%, respectively. This method was free from interference by hemoglobin, bilirubin, ascorbate, chyle, various sugars, sugar alcohol and myo-inositol phosphates. With the use of myo-inositol as a standard solution, the serum myo-inositol concentration (mean+/-SD) was significantly greater in patients with diabetes mellitus (DM) without nephropathy (73.0+/-13.8 micromol/l, n=7) than in healthy individuals without DM (61.0+/-12.4 micromol/l, n=20). The urinary myo-inositol concentration was also significantly greater in patients with DM without nephropathy (793.3+/-870.3 micromol/l, n=7) than in healthy individuals without DM (76.0+/-63.0 micromol/l, n=13)., Conclusions: This new method is simple, sensitive and enables quantitative analysis of myo-inositol.

The phosphatidylinositol 3-kinase (PI3K) signaling pathway is important for the regulation of a number of cellular responses. Serine/threonine kinase Akt (protein kinase B; PKB) is downstream of PI3K and activated by growth factors. This study found that erythropoietin (EPO) induced tyrosine phosphorylation of Akt in a time- and dose-dependent manner in EPO-dependent human leukemia cell line UT-7/EPO. In vitro kinase assay using histone H2B and glucose synthase kinase as substrates demonstrated that Akt was actually activated by EPO. EPO-induced phosphorylation of Akt was completely blocked by a PI3K-specific inhibitor, LY294002, at 10 micromol/L, indicating that activation of Akt by EPO is dependent on PI3K activity. In addition, overexpression of the constitutively active form of Akt on UT-7/EPO cells partially blocked apoptosis induced by withdrawal of EPO from the culture medium. This finding suggested that the PI3K-Akt activation pathway plays some role in the antiapoptotic effect of EPO. EPO induced phosphorylation of a member of the trancription factor Forkhead family, FKHRL1, at threonine 32 and serine 253 in a dose- and time-dependent manner in UT-7/EPO cells. Moreover, results showed that Akt kinase activated by EPO directly phosphorylated FKHRL1 protein and that FKHRL1 phosphorylation was completely dependent on PI3K activity as is the case for Akt. In conjunction with the evidence that FKHRL1 is expressed in normal human erythroid progenitor cells and erythroblasts, the results suggest that FKHRL1 plays an important role in erythropoiesis as one of the downstream target molecules of PI3K-Akt.

Background/aims: Blood concentration levels of alpha-fetoprotein like the Lens culinaris agglutinin-reactive fraction (AFP-L3) are a useful marker for predicting the long-term prognosis of hepatocellular carcinoma. This study investigated the relationship between serum AFP-L3 and various imaging modalities., Methods: Sixty-three patients with small hepatocellular carcinomas < or = 2 cm in diameter were studied. Serum AFP-L3 concentrations were measured by lectin-affinity electrophoresis coupled with antibody-affinity blotting and expressed as % AFP-L3 (the percent of AFP-L3 as total AFP). A clinical "cutoff level" of 10% was used in this study to indicate the presence of hepatocellular carcinoma. Selective hepatic intraarterial digital subtraction angiography (DSA), ultrasonographic angiography with carbon dioxide microbubbles (USAG), and computed tomography during arterial portography (CTAP) were performed to evaluate the hemodynamics of hepatic nodules., Results: Fourteen (22.2%) of the 63 patients were positive for % AFP-L3. The % AFP-L3 levels (n=45, 4.4%) of patients with hypervascular tumors were significantly higher than those (n=15, 0.0%) of patients with isovascular or hypovascular tumors as determined by USAG (p=0.0061). The % AFP-L3 levels (n=53, 4.4%) of patients with a negative portal blood supply were significantly higher than the % AFP-L3 levels (n=7, 0.0%) of patients with a positive portal blood supply as determined by CTAP (p=0.0140). The % AFP-L3 levels of patients with tumors with a long doubling time (DT) were significantly lower than for patients with tumors with a short DT (p=0.0176)., Conclusion: AFP-L3 is a positive indicator which may be more specific for small advanced hepatocellular carcinoma.

TRK-820, a new type of 4,5-epoxymorphinan derivative, was investigated in vivo for antinociceptive activities and its selectivity on various opioid receptors in mice. TRK-820 given s.c. or p.o. was found to be 351- and 796-fold more potent than U50,488H with acetic acid-induced abdominal constriction test. The duration of the antinociceptive effect produced by TRK-820 was longer than that produced by mu-opioid receptor agonist morphine or other kappa-opioid receptor agonists. In addition, with four other antinociceptive assays, low temperature hot plate (51 degrees C), thermal tail flick, mechanical tail pressure and tail pinch tests, TRK-820 was also found to be 68- to 328-fold more potent than U-50488H, and 41- to 349-fold more potent than morphine in producing antinociception, as comparing the weight of the different compound. However, TRK-820 was less active in inhibiting the high temperature (55 degrees C) hot plate response. The antinociceptive effects produced by TRK-820 were inhibited by nor-BNI, but not by naloxone or naltrindole (NTI) with the abdominal constriction test, indicating that the antinociception is selectively mediated by the stimulation of kappa-, but not mu- or delta-opioid receptors. Co-administration of TRK-820 with morphine slightly enhanced the antinociception induced by morphine in the mouse hot plate test. On the other hand, pentazocine significantly reduced the morphine-induced antinociception. TRK-820 produced sedation at doses, which are much higher than the doses for producing antinociception. These results indicate that the potent antinociception induced by TRK-820 is mediated via the stimulation of kappa-, but not mu- or delta-opiod receptors.

Effects of inhibitors of arachidonic acid (AA) cascade on the development of fatty liver, cirrhosis, glutathione S-transferase placental form (GST-P)-positive preneoplastic nodules, neoplastic nodules and generation of 8-hydroxydeoxyguanosine (8-OHdG), caused by a choline-deficient, L-amino acid-defined (CDAA) diet, were examined in Fischer 344 male rats by feeding CDAA diet supplemented with the inhibitors for 12 and 30 weeks. None of the inhibitors affected fatty liver. Among cyclooxygenase (COX) inhibitors, an irreversibly acting acetylsalicylic acid and a long-acting piroxicam, and to a much lesser extent the short-acting ibuprofen but not indomethacin, inhibited the development of cirrhosis, GST-P-positive and neoplastic nodules and generation of 8-OHdG. A phospholipase A2 inhibitor p-bromophenacylbromide (BPB) also exerted similar but lesser extent of inhibitory effects. Lipoxygenase inhibitors quercetin and nordihydroguiaretic acid inhibited GST-P-positive nodules but not cirrhosis or 8-OHdG. Present results suggest that perturbed AA cascade, particularly augmented COX pathway, might play key roles in the causation of liver lesions in the CDAA diet model., (Copyright 1998 Elsevier Science B.V. All rights reserved.)

Inducibility of oxidative stress by menadione-associated redox cycling activation under redox-enzyme modulated conditions was examined in F344 male rat liver, by monitoring 8-hydroxydeoxyguanosine (8-OHdG) levels in DNA and hepatocyte injury. Further, the treatment-associated liver tumor-initiating, -promoting and -progressing potentials were assessed in terms of development of enzyme-altered preneoplastic foci, neoplastic nodules and hepatocellular carcinomas. With or without menadione, redox-enzyme modulation consisting of increased cytochrome P450 reductase by phenobarbital (PB), depletion of glutathione by phorone, inhibition of DT-diaphorase by dicumarol, with or without further supplement of iron, caused both 8-OHdG production and hepatocyte necrosis. Thus-induced oxidative stress exerted liver tumor promoting-activity in N-nitrosodiethylamine (DENA)-initiated rats, but neither initiating activity when promoted by 0.05% PB diet for 64 weeks, nor progressing activity when the oxidative stress was given for 33 weeks to preneoplastic nodule-bearing rats which was induced by DENA.

The effects of a potent and highly selective nonpeptide delta opioid receptor agonist, 2- methyl-4a alpha-(3-hydroxyphenyl)-1,2,3,4,4a,5,12,12a alpha- octahydroquinolino [2,3,3,-g] isoquinoline (TAN-67), on morphine-induced antinociception were examined using the warm-plate (51 degrees C) method. When a peptide delta 1 opioid receptor agonist, [D-Pen2, Pen5]enkephalin (DPDPE), was co-administered with i.c.v. morphine, low-dose morphine-induced antinociception was significantly increased. In contrast, i.c.v. co-administration of a peptide delta 2 opioid receptor agonist, [D-Ala2]deltorphin II (DELT), with morphine did not affect the morphine-induced antinociception. When morphine and TAN-67 were co-administered i.c.v., low-dose morphine-induced antinociception was significantly increased. Moreover, when TAN-67 and morphine were co-administered s.c., the morphine dose-response curve shifted to the left and the ED50 value of morphine decreased. These effects DPDPE and TAN-67 were antagonized by the delta opioid receptor antagonist naltrindole (NTI) and the delta 1 opioid receptor antagonist 7-benzylidenenaltrexone (BNTX) not by the delta 2 opioid receptor antagonist naltriben (NTB). Moreover, the mu opioid receptor antagonist beta-FNA also antagonized the effects of DPDPE and TAN-67. These results suggest that the effect of TAN-67 may result from the activation of central delta 1 opioid receptors, since the effect of TAN-67 was antagonized by NTI and BNTX, but not NTB. Furthermore, since pretreatment with beta-FNA also antagonized the effects of both DPDPE and TAN-67, a beta-FNA-sensitive site, i.e. a mu-delta complex site, may play an important role in the modulation of morphine-induced antinociception.

A cerebral injury was induced by the bilateral common carotid artery occlusion and recirculation in spontaneously hypertensive rats (SHRs). Employing this ischemia-recirculation rat model, the effects of beraprost sodium (beraprost) on (1) lipid peroxide formation, (2) the increase in the brain water content and (3) neurological signs were examined. In a dosage of 25 micrograms kg-1 or higher, beraprost, administered orally, significantly inhibited the formation of lipid peroxides in the brain and serum induced by cerebral ischemia and subsequent recirculation in a dose-dependent manner. Beraprost also alleviated ptosis and markedly inhibited abnormal running behaviour caused by the ischemia and subsequent recirculation. In addition, although administration of beraprost did not cause marked inhibition of the increase in the brain water content (used as an index of cerebral oedema) during the first 3 h after recirculation, it restored the normal brain water content within 24 h after recirculation. Therefore, this effect was observed evidently later than the effect of inhibition of lipid peroxide formation. Moreover, administration of beraprost resulted in improvement in the symptoms accompanying the ischemic treatment. These results suggest that beraprost is potentially useful for or treatment of the pathological state accompanying cerebral infarction.