RATIONALE:In vitro studies have identified a series of decahydroisoquinoline compounds with differential selectivity for the subunits that comprise AMPA/kainic acid receptors. Compounds have been identified that have preferential activity at AMPA receptors (LY302679), whereas others (LY377770) have affinity for GluR5-kainic acid preferring subunit, which is activated by ATPA and kainic acid.OBJECTIVES:These studies set out to determine if locomotor activity could differentiate these profiles in vivo.METHODS:Locomotor activity was assessed in photocell drums in male Lister Hooded rats.RESULTS:AMPA, kainic acid and the GluR5 selective agonist ATPA, all suppressed spontaneous locomotor activity (SLA) in rats at doses of 1.0, 5.0 and 20 mg/kg resp. All three agonists achieve micromolar concentrations measured in whole brain after dosing with 10 mg/kg SC. The decahydroisoquinoline antagonist compounds, LY302679 (GluR2), LY293558 (GluR2, 5) and LY377770 (GluR5) all decreased SLA in rats (ED(min) 2.5, 5.0 and 20 mg/kg respectively). The rank order of potency at GluR2 subunits (LY302679>LY293558>LY377770) was reflected in the same rank order of activity for suppression of SLA. LY293558 reversed the suppression of SLA induced by all three agonists (0.62--2.5 mg/kg). LY377770 reversed the effects of ATPA only (ED(min) 1.0 mg/kg), LY302679 (ED(min) 2.5 mg/kg) attenuated the effect of kainic acid but was ineffective against AMPA and ATPA.CONCLUSIONS:Both agonist and antagonist suppression of SLA is associated with greater affinity for the GluR2 subunit, while compounds with affinity for the GluR5 subunit were less potent in suppressing SLA.

Recent developments in the molecular biology and pharmacology of α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors has led to the discovery of selective, potent and systemically active AMPA receptor potentiators. These molecules enhance synaptic transmission and evidence suggests that they play important roles in plasticity and cognitive processes. Activation of AMPA receptors also increases neuronal activation and activity-dependent signalling, which may increase brain-derived neurotrophic factor (BDNF) expression and enhance cell proliferation in the brain. We therefore hypothesised that an AMPA receptor potentiator may provide neurotrophic effects in rodent models of Parkinson's disease. In the present studies we report that the potent and selective AMPA receptor potentiator, R,S-N-2-(4-(4-Cyanophenyl)phenyl)propyl 2-propanesulfonamide (LY404187), provides both functional, neurochemical and histological protection against unilateral infusion of 6-hydroxydopamine into the substantia nigra or striatum of rats. The compound also reduced 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced toxicity in mice. Interestingly, we were also able to observe large functional and histological effects when we delayed treatment until after cell death had occurred (3 or 6 days after 6-hydroxydopamine infusion), supporting a neurotrophic mechanism of action. In addition, LY404187 provided a dose-dependent increase in growth-associated protein-43 expression in the striatum. Therefore, we propose that AMPA receptor potentiators offer the potential of a new therapy to halt the progression and perhaps repair the degeneration in Parkinson's disease.

The aim of the present studies was to examine the ability of a potent, systemically active, selective Group II mGlu receptor (mGluR2/3) agonist, 1R,4R,5S,6R-2-oxa-4-minobicyclo[3.1.0.]hexane-4,6-dicarboxylate (LY379268) to provide both functional relief and neuroprotection in rodent models of Parkinson's disease (PD). In functional studies, intracerebroventricular administration of LY379268 (1, 5, 10, 20 nmol/2 microl) produced a dose-dependent increase in locomotor activity in the reserpine (5 mg/kg ip)-treated rat. In contrast, systemic administration of LY379268 (0.1, 1, 10 mg/kg ip) did not reverse reserpine-induced akinesia and failed to effect rotational behaviour 1 month after unilateral lesioning of the nigrostriatal tract by 6-hydroxydopamine (6-OHDA; 4 microg infused into the substantia nigra (SN)). In neuroprotective studies, animals were treated with LY379268 (10 mg/kg/day ip) either for 7 days following 6-OHDA injection into the SN (4 microg) or for 21 days following 6-OHDA injection into the striatum (10 microg) before measurement of tyrosine hydroxylase immunoreactivity in the striatum and/or SN as an index of neuroprotection. LY379268 provided some protection against nigral infusion of 6-OHDA and also some functional improvement and correction of dopamine turnover was observed. The compound also provided significant protection in the striatum and some protection in the SN against striatal infusion of 6-OHDA. These data suggest that activation of Group II mGlu receptors can provide some protection in models of PD, while their role in providing functional improvement is less clear.

In the present studies we have examined the effects of a new calcium channel blocker, LY393615 ((N-Butyl-[5,5-bis-(4-fluorophenyl)tetrahydrofuran-2-yl]methylamine hydrochloride, NCC1048) in a model of hypoxia-hypoglycaemia in vitro and in a gerbil model of global and in two rat models of focal cerebral ischaemia in vivo. Results indicated that LY393615 protected against hypoxia-hypoglycaemic insults in brain slices and also provided significant protection against ischaemia-induced hippocampal damage in gerbil global cerebral ischaemia when dosed at 10, 12.5 (P<0.05) or 15 mg/kg i.p. (P<0.01) 30 min before and 2 h 30 min after occlusion. The compound penetrated the brain well after a 15 mg/kg i.p. dose and had a half-life of 2.5 h. In further studies LY393615 was protective 1 h post-occlusion when administered at 15 mg/kg i.p. followed by 2 doses of 5 mg/kg i.p. 2 and 3 h later. LY393615 dosed at 15 mg/kg i.p. followed by 2 further doses of 5 mg/kg i.p. (2 and 3 h later) also produced a significant reduction in the infarct volume following Endothelin-1 (Et-1) middle cerebral artery occlusion in the rat when administration was initiated immediately (P<0.01) or 1 h (P<0.05) after occlusion. The compound was also evaluated in the intraluminal monofilament model of focal ischaemia. The animals had the middle cerebral artery occluded for 2 h, and 15 min after reperfusion LY393615 was administered at 15 mg/kg i.p. followed by 2 mg/kg/h i.v. infusion for 6 h. There was no reduction in infarct volume using this dosing protocol. In conclusion, in the present studies we have reported that a novel calcium channel blocker, LY393615, with good bioavailability protects against neuronal damage caused by hypoxia-hypoglycaemia in vitro and both global and focal cerebral ischaemia in vivo. The compound is neuroprotective when administered post-occlusion and may therefore be a useful anti-ischaemic agent.

Clonidine is an adrenergic agonist with high affinity for alpha2 adrenoceptors that also has affinity for imidazoline receptors. Clonidine has previously been shown to reduce immobility in the forced swim test (FST) in mice. In the present study, this effect was blocked by idazoxan (0.06 mg/kg s.c.) and by yohimbine (1.0 mg/kg s.c.) suggesting that clonidine's effects in this test are mediated via its action at alpha2 sites. Imidazoline I2 site ligands have been shown to inhibit monoamine oxidase and thus may also have antidepressant activity. Three compounds with selective affinity for I2 receptors (BU224, BU239, BDF 8082) were also tested in the FST. These compounds showed no activity either alone or in combination with a subthreshold dose of imipramine in the FST. These results suggest that I2 receptor ligands do not show antidepressant-like activity in the FST in mice. Furthermore the activity of the mixed alpha2/I1 agonist clonidine is most likely to be due to its action at alpha2 sites.

In the present studies, we have evaluated the effects of N-[4-(2-¿[(3-Chlorophenyl)methyl]amino¿ethyl)phenyl]-2-thiophenecarbo ximidamide dihydrochloride (ARL 17477) on recombinant human neuronal NOS (nNOS) and endothelial NOS (eNOS). We then carried out pharmacokinetic studies and measured cortical nitric oxide synthase (NOS) inhibition to determine that the compound crossed the blood brain barrier. Finally, the compound was evaluated in a model of global ischaemia in the gerbil and two models of transient focal ischaemia in the rat. The IC(50) values for ARL 17477 on human recombinant human nNOS and eNOS were 1 and 17 microM, respectively. ARL 17477 (50 mg/kg i.p.) produced a significant reduction in the ischaemia-induced hippocampal damage following global ischaemia when administered immediately post-occlusion, but failed to protect when administration was delayed until 30 min post-occlusion. In the endothelin-1 model of focal ischaemia, ARL 17477 (1 mg/kg i.v.) significantly attenuated the infarct volume when administered at either 0, 1 or 2 h post-endothelin-1 (P<0.05). In the intraluminal suture model, ARL 17477 at both 1 and 3 mg/kg i.v. failed to reduce the infarct volume measured at 1, 3 or 7 days post-occlusion. These results demonstrate that ARL 17477 protects against global ischaemia in gerbils and provides some reduction in infarct volume following transient middle cerebral artery occlusion in rats, indicating that nNOS inhibition may be a useful treatment of ischaemic conditions.

The chondroitin ABC lyase digestion products of normal human femoral condyle articular cartilage and of purified aggrecan were analyzed for their mono- and nonsulfated disaccharide composition. Changes in the total tissue chemistry were most pronounced during the period from birth to 20 years of age, when the -[GlcAbeta,3GalNAc6]- disaccharide content increased from approximately 50% to 85% of the total disaccharide content and there was a concomitant decrease in the content of the 4-sulfated disaccharide. In general, the disaccharide content of the deeper layers of immature cartilage were richer in the 4-sulfated residue than the upper regions of the tissue. As the tissue aged and decreased in thickness, the disaccharide composition became more evenly 6-sulfated. The newly synthesized chondroitin sulfate chains had a similar composition to the endogenous chains and also underwent the same age and zonal changes. The monoclonal antisera 3B3(+) and 2B6(+) were used to immunolocalize the unsaturated 6- and 4-sulfated residues generated at the reducing termini of the chondroitin sulfate chains by digestion with chondroitin ABC lyase, and these analyses indicated that the sulfation pattern at this position did not necessarily reflect the internal disaccharide composition of the chains. In summary, the sulfation pattern of chondroitin sulfate disaccharides from human normal articular cartilage varies with the age of the specimen, the position (topography) on the joint surface, and the zone of cartilage analyzed. Furthermore, these changes in composition are a consequence of both extracellular, post-translational processing of the core protein of aggrecan and changes in the sulfotransferase activity of the chondrocyte.

Following reports that ascorbic acid (AA) blocks NMDA receptors, we examined its possible neuroprotective properties in vivo (gerbil bilateral carotid artery occlusion model: BCAO) and in vitro (ischaemia-induced dopamine (DA) release in brain slices). Five minutes of BCAO caused substantial cell loss of 90–95% and 40–50% in gerbil CA1 hippocampus and striatum, respectively, measured in haematoxylin and eosin-stained sections, 5 days post-insult. AA (500 mg kg−1 day−1 i.p. for 312 days, first dose 1 h before occlusion) significantly (P<0.05) reduced striatal cell loss (from 40 to 13%) while only reducing CA1 cell loss from 95 to 88%. A lower dose (250 mg kg−1 day−1 i.p. for 312 days) was ineffective in either region. AA (750 mg kg−1 day−1 i.p. for 312 days) caused significant striatal protection (cell loss reduced from 49 to 20%) if treatment was initiated 1 h before occlusion. Initiation of treatment immediately post occlusion did not cause significant protection. Neither treatment regime protected CA1 hippocampus. In separate experiments we examined the effect of AA on DA release, monitored by voltammetry, in an in vitro model of striatal ischaemia. Four DA release variables were measured: Ton — time from initiation of ischaemia to the onset of DA release, Tpk— the time from onset of DA release to maximum, δDA/δt — the mean rate of DA release and [DA]max — the maximum extracellular DA concentration. Control values in drug-naive slices were: Ton=193±8 s, Tpk=24±4 s, [DA]max=69±6 μM and δDA/δt=4.2±0.7 μM s−1 (means±S.E.M., n=15). 212 h pretreatment with AA (0.4 to 10 mM) did not affect Ton or [DA]max but increased Tpk and decreased δDA/δt (P<0.05) with an EC50 of 1.66 mM. NMDA (100 μM) shortened Ton. N-ethylmaleimide (20 μM) had no effect on the response to AA but potentiated the action of NMDA on Ton. AA (2 or 10 mM) had no effect on the response to NMDA. We conclude that AA is neuroprotective against global ischaemia in the striatum and that some of this action may be due to attenuation of ischaemia-induced DA release. This action is mediated neither by blockade of the NMDA receptor nor modulation of its redox status.

Male Dunkin Hartley guinea-pigs have been shown to develop spontaneous osteoarthritis, in the knee joint, which is histologically apparent from the age of 3 months onwards. We have used capillary electrophoresis (CE) to examine subtle changes in the sulfation of chondroitin in guinea-pig articular and xiphisternal cartilage. An age-related increase in the 6:4 sulfation ratio of chondroitin was observed, with the medial tibial plateau developing more rapidly than the other joint surfaces. The observed sulfation patterns may be related to the onset of spontaneous osteoarthritis which, in the guinea-pig, develops initially on the medial tibial plateau. Chondroitin from patellar groove cartilage of animals between 3 and 12 months of age always had a significantly lower 6:4 sulfate ratio than the other joint surfaces.

We report here the presence of a bioactive compound in the secretion of the accessory salivary glands (ASGs) of Nucella lapillus. We have purified the compound using HPLC and identified it as serotonin by mass spectrometry, UV spectroscopy, HPLC and capillary electrophoresis. Serotonin was not found in the secretions of the acinous salivary glands or the hypobranchial gland. The amount of serotonin in the secretion of the ASGs does not show seasonal or regional variation.

The metabolism of [3-14C]coumarin has been studied in hepatic microsomes from control (corn-oil treated) and Aroclor 1254-treated (100 mg/kg body weight/day, 5 days, ip) rats. [3-14C]Coumarin metabolites in incubate extracts were separated by HPLC and identified by comparison with the retention times of known coumarin metabolites. The major product produced by incubation of 0.25-2.5 mM-[3-14C]coumarin with both control and Aroclor 1254-induced hepatic microsomes was a novel coumarin metabolite. This novel metabolite was extracted from pooled microsomal incubations, purified by semi-preparative HPLC and identified by mass spectrometry as o-hydroxyphenylacetaldehyde (o-HPA). Some possible pathways for the formation of o-HPA from coumarin are proposed.

Cell-free 100,000 g supernatants from liver, kidney, lung and caecum of rat, rabbit and guinea-pig were compared for their ability to transform prostaglandins F2α, D2, E2 and 9α, 11β-prostaglandin F2 (11epi-PGF2α) to metabolic products. Experiments utilized multitritiated substrate PGs, with assessment of biotransformation by TLC, HPLC and GC/MS. PGF2α was converted via the sulphasalazine analogue-inhibitable NAD+-dependent 15-hydroxy-prostaglandin dehydrogenase pathway (15-PGDH), with high activity (>5 pmol/min/mg protein) in all 12 systems except rat and rabbit liver (e.g. guinea-pig kidney and rat caecum both 64 pmol/min/mg; rat liver 0.3 pmol/min/mg), forming 15-keto and 13,14-dihydro-15-keto metabolites as determined by TLC, HPLC and GC/MS. Prostaglandin D2 was not transformed in similar fashion in NAD+- or NADP+-supplemented incubations in any of the 12 cytosolic systems. However, PGD2 was converted to a single product identified by TLC, HPLC and GC/MS as 9α, 11β-PGF2 in certain of the systems when supplemented with an NADPH regenerating system, with high activity in guinea-pig kidney (55.0 pmol/min/mg), guinea-pig liver (27.5 pmol/min/mg) and rabbit liver (13.7 pmol/min/mg) and less than 5 pmol/min/mg in 8 of the remaining 9 systems. This stereospeciflc 11-ketoreductase of rabbit and guinea-pig liver was stable to 10 min heating at 50°, dialysis, storage at −20° and repeated freeze/thawing but was not inhibited by sulphasalazine analogues. The 11-ketoreductase had a markedly different tissue profile from PGE2 9-ketoreductase, which was shown to convert PGE2 stereospecifically to 9α, 11α-prostaglandin F2 (PGF2α) and was present at highest activity in rabbit liver and kidney. Evidence was obtained that 9α, 11β-PGF2 was actively transformed by the sulphasalazine-inhibitable 15-PGDH pathway at approximately one third of the rate of PGF2α with high activity in several cytosolic systems (e.g. rat caecum, guinea-pig liver and kidney), suggesting that further transformation in vivo of this biologically active product of PGD2 metabolism could be initiated by this route.

gamma-Hexachlorocyclohexane stimulates arachidonic acid release from macrophage phospholipids. It is also a powerful stimulator of leukotriene C4 production, yet (by comparison with zymosan) produces only a small effect on prostaglandin production. This suggests that synthesis of leukotrienes and prostaglandins can be independently regulated. The most likely mechanism of action of gamma-hexachlorocyclohexane is through its effect on phosphatidylinositol metabolism.

Chemischer InformationsdienstVolume 15, Issue 4 Natural Products ChemInform Abstract: SYNTHESIS OF 8,9-LEUKOTRIENE C3 AND D3 S. R. BAKER, S. R. BAKERSearch for more papers by this authorJ. R. BOOT, J. R. BOOTSearch for more papers by this authorS. E. MORGAN, S. E. MORGANSearch for more papers by this authorD. J. OSBORNE, D. J. OSBORNESearch for more papers by this authorW. J. ROSS, W. J. ROSSSearch for more papers by this authorP. R. SHRUBSALL, P. R. SHRUBSALLSearch for more papers by this author S. R. BAKER, S. R. BAKERSearch for more papers by this authorJ. R. BOOT, J. R. BOOTSearch for more papers by this authorS. E. MORGAN, S. E. MORGANSearch for more papers by this authorD. J. OSBORNE, D. J. OSBORNESearch for more papers by this authorW. J. ROSS, W. J. ROSSSearch for more papers by this authorP. R. SHRUBSALL, P. R. SHRUBSALLSearch for more papers by this author First published: January 24, 1984 https://doi.org/10.1002/chin.198404334Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume15, Issue4January 24, 1984 RelatedInformation

The following high performance liquid chromatography system was found suitable for separating most lipoxygenase metabolites of arachidonic acid: Techsphere 5-C18 column, eluting solvent methanol:water:acetic acid (65:35:0.06 v/v), pH 5.3. Comparisons with other packing materials and solvent systems are described. The method could be used to identify lipoxygenase products released from mouse macrophage cells stimulated with gamma-hexachlorocyclohexane. Detection limits between 1 and 10 ng were obtained.

An asymmetric epoxidation provides a short convenient synthesis of 8,9-leukotrienes C3 and D3.

An asymmetric epoxidation provides a short convenient synthesis of 8,9-leukotrienes C 3 and D 3 .

Eight synthetic isomers of hydroxy-6-S-cysteinylglycine -7,9,11,14-eicosatetraenoic acid were compared with authentic guinea pig SRS-A using UV spectroscopy, high performance liquid chromatography and soybean lipoxygenase. It was found that only the 5S, 6R 7, 9trans 11,14cis isomer was similar to SRS-A in all respects. The 5S, 6R 7trans, 9,11,14 cis isomer shows similar UV and HPLC characteristics but differs in that it spontaneously undergoes a 1,7 hydride shift reaction and unexpectedly does not react with soybean lipoxygenase.

AbstractBei der Umsetzung von racemischem Leukotrien‐A4‐methylester (II) mit Glutathion erhält man nach Hydrolyse im wesentlichen das Addukt (I) neben einem Isomeren, dem die Struktur (IV) zukommt.