Enhancement of ambulation-increasing effect of methamphetamine by peripherally-administered 6R-L-erythro-5,6,7,8-tetrahydrobiopterin (R-THBP) in mice

Behavioral effects of 6R-L-erythro-5,6,7,8-tetrahydrobiopterin (R-THBP), a co-factor for tyrosine hydroxylase and tryptophan hydroxylase, were investigated by means of ambulatory activity in mice. Single administration of R-THBP (50 and 100 mg/kg, s.c.) showed no significant effect on the mouse's ambulatory activity for 5 hr. The ambulation-increasing effect of methamphetamine (2 mg/kg, s.c.) was dramatically enhanced and prolonged by the pretreatment with R-THBP (100 mg/kg, s.c.) 0, 2, 6, 12 and 24 hr before, but not 18 or 36 hr before, the methamphetamine administration. However, when combined administration of R-THBP (100 mg/kg, s.c., 2 hr before) with methamphetamine (2 mg/kg, s.c.) was repeated at intervals of 3-4 days, the enhancement by R-THBP of the methamphetamine effect was observed only in the 1st and 2nd administration, but not in the later administration. The pretreatment with R-THBP (100 mg/kg, s.c., 2 hr before) enhanced the ambulation-increasing effect of ephedrine (80 mg/kg, i.p.), but failed to modify those of cocaine (20 mg/kg, s.c.), mazindol (2.5 mg/kg, s.c.), bromocriptine (8 mg/kg, i.p.), morphine (20 mg/kg, s.c.) and scopolamine (0.5 mg/kg, s.c.). It is noteworthy that R-THBP differentially modifies the ambulation-increasing effect of the above-mentioned drugs.     

(6R,6S)-5,8,10-trideaza-5,6,7,8-tetrahydrofolate and 6(R,6S)-5,8,10-trideaza-5,6,7,8-tetrahydropteroyl-L-ornithine as potential antifolates and antitumor agents

(6R,6S)-5,8,10-Trideaza-5,6,7,8-tetrahydropteroic acid was synthesized in several steps from 4,4-(ethylenedioxy)-cyclohexanone and [4-(tert-butyloxycarbonyl)benzyl]triphenylphosphonium bromide and was elaborated to (6R,6S)-5,8,10-trideaza-5,6,7,8-tetrahydropteroyl-L-glutamic acid and (6R,6S)-5,8,10-trideaza-5,6,7,8-tetrahydropteroyl-L-ornithin e. Compound 1 was found to be a good substrate for partially purified mouse liver folypolyglutamate synthetase (FPGS), with a Michaelis constant (Km = 15 microM) comparable to that reported for the reduced folate substrate (6S)-5,6,7,8-tetrahydropteroyl-L-glutamic acid and for (6R,6S)-5,10-dideaza-5,6,7,8-tetrahydropteroyl-L-glutamic acid (DDATHF). However, in striking contrast to DDATHF, which is potently cytotoxic, 1 failed to inhibit tumor cell growth in culture at concentrations of up to 100 microM. These results suggested that the NH at position 8 of DDATHF is important for cytotoxic activity but not for polyglutamylation. Just as 1 was a good substrate for FPGS, the ornithine analogue 2 proved to be among the more potent competitive inhibitors of this enzyme discovered to date, with a Ki,s of 10 microM. While the binding affinity of 2 was lower than that reported for 5,6,7,8-tetrahydropteroyl-L-ornithine (H4PteOrn), very substantial FPGS inhibition was observed even though N5,N8, and N10 in H4PteOrn were replaced by carbon. Binding to FPGS thus appears to be tolerant of bioisosteric replacements made simultaneously in ring B and the bridge region. Neither 1 nor 2 was active in preventing cell growth in culture at concentrations of up 100 microM. The N delta-hemiphthaloyl derivative of 2, synthesized as a potential prodrug, was also inactive.     

Involvement of dopamine autoreceptors in the hypoactivity induced by 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) in mice.

The effect of 8-OH-DPAT, a 5-HT1A receptor agonist, on the locomotor activity was analyzed in Albino Swiss mice. The studied drug (0.5-5 mg/kg) inhibited the spontaneous locomotor activity in mice. The hypoactivity induced by 8-OH-DPAT (1.5 mg/kg) was abolished by the dopamine (D1 and D2) receptor antagonist-haloperidol (0.00125 and 0.0025 mg/kg, but not in higher doses) and by the D2 antagonist with affinity for 5-HT1A and 5-HT2 receptors-spiperone (0.0025 and 0.005 mg/kg, but not in higher doses). The effect of 8-OH-DPAT was slightly reduced by the alpha 2-adrenoceptor antagonists: idazoxan (4 mg/kg), yohimbine (2 and 4 mg/kg) and rauwolscine (4 mg/kg). On the other hand, the non-selective 5-HT antagonist metergoline (0.5-4 mg/kg), the 5-HT1A antagonist NAN-190 (0.5-2 mg/kg), the beta-adrenoceptor blockers with high affinity for 5-HT1A and 5-HT1B receptors: pindolol and SDZ 21009 (2-8 mg/kg) and the agonist/antagonist of 5-HT1A receptors ipsapirone (2.5 and 5 mg/kg) did not affect the 8-OH-DPAT-induced hypoactivity. The obtained results suggest that the reduction of the spontaneous locomotor activity induced by 8-OH-DPAT results from a stimulation of dopamine autoreceptors, but not 5-HT receptors. Involvement of an alpha 2-adrenergic mechanism cannot be excluded.     

Inhibition of neuronal nitric oxide synthase by 4-amino pteridine derivatives: structure-activity relationship of antagonists of (6R)-5,6,7,8-tetrahydrobiopterin cofactor.

The family of nitric oxide synthases (NOS) catalyzes the conversion of L-arginine to L-citrulline and nitric oxide (NO), an important cellular messenger molecule which has been implicated in the pathophysiology of septic shock and inflammatory and neurodegenerative disease states. NOS can be maximally activated by the ubiquitous cofactor, (6R)-5,6,7,8-tetrahydrobiopterin (H(4)Bip), and antagonists of H(4)Bip may be of therapeutic importance to inhibit pathologically high NO formation. The 4-amino substituted analogue of H(4)Bip was reported to be a potent NOS inhibitor. Therefore, we developed a series of novel 4-amino pteridine derivatives, anti-pterins, to pharmacologically target the neuronal isoform of nitric oxide synthase (NOS-I). To functionally characterize the pterin/anti-pterin interaction and establish a structure-activity relationship (SAR), we systematically altered the substituents in the 2-, 4-, 5-, 6-, and 7-position of the pteridine nucleus. Varying the substitution pattern in the 2-, 5-, and 7-position resulted in no significant inhibitory effect on enzyme activity. In contrast, bulky substituents in the 6-position, such as phenyl, markedly increased the inhibitory potency of the reduced 4-amino-5,6,7,8-tetrahydropteridines, possibly as a consequence of hydrophobic interactions within NOS-I. However, this was not the case for the aromatic 4-amino pteridines. Interestingly, chemical modification of the 4-amino substituent by dialkyl/diaralkylation together with 6-arylation of the aromatic 2,4-diamino pteridine resulted in potent and efficacious inhibitors of NOS-I, suggesting possible hydrophilic and hydrophobic interactions within NOS-I. This SAR agrees with (a) the recently published crystal structure of the oxygenase domain of the inducible NOS isoform (NOS-II) and (b) the comparative molecular field analysis of selected NOS-I inhibitors, which resulted in a 3D-QSAR model of the pterin binding site interactions. Further optimization should be possible when the full length structure of NOS-I becomes available.     

MPTP-induced hypoactivity in mice: reversal by L-dopa

Three experiments were performed to study the subchronic effects of treatment with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 2 x 40 mg/kg subcutaneously two weeks before testing) in C57 BL/6 mice upon spontaneous motor activity and the reversal of the long-term behavioural changes by acute treatment with L-Dopa. Mice treated with MPTP showed a drastic reduction of striatal dopamine levels (-88%) associated with reductions of all three parameters of spontaneous motor activity, i.e. locomotion, rearing and total activity, during both the initial, exploratory, stage (first 90 min), and later stages of the 3- or 4-hr test periods. L-Dopa (5-80 mg/kg subcutaneously) injected 60 min. after the start of testing dose-dependently improved all three parameters studied in MPTP treated mice with 10 mg/kg being the lowest dose causing a significant effect, while doses above 20 mg/kg caused hyperactivity. During the initial period, rearing activity in MPTP mice was to a variable degree suppressed by the L-Dopa treatment (20-80 mg/kg); these reductions were followed by enormous increases in motor activity by the 40 mg/kg (locomotion) and 80 mg/kg (total activity) L-Dopa groups. Both the degree and duration of the L-Dopa-induced hypoactivity for locomotor behaviour increased dose-dependently in control mice. No suppressive effects of L-Dopa were obtained for total activity in control mice, although the 80 mg/kg L-Dopa doses evoked hyperactivity for up to 90 min. following treatment for both locomotion and total activity.(ABSTRACT TRUNCATED AT 250 WORDS)     

4（R）—（6—氨基—9H—嘌呤—9—基）—2（R）—（羟甲基）四氢呋喃—3（R）—醇的合成

为寻找抗HIV化合物,我们以D－核糖为原料,经甲基化、硅烷基化、还原裂解反应制得重要中间体1－脱氧核糖（5）,再通过形成环状亚砜化合物,与NaN3发生反应后,经过还原、缩合、环合、氨化、脱保护基反应制得异脱氧腺嘌呤核苷（1）,各步反应收率均超过70％。其抗HIV活性测定尚在进行中。     

4（R）—（6—氨基—9—嘌呤基）—2（R）—（羟甲基）四氢呋喃—3（R）—醇的合成

为寻找抗免疫缺陷病毒化合物,以D－核糖为原料,经甲基化、硅烷基化、还原裂解反应制得重要中间体1－脱氧核糖（5）,再通过形成环状亚砜化合物,与NaN3发生反应后,经过还原、缩合、环合、氨化、脱保护基反应制得异脱氧腺嘌呤核苷（1）,各步反应收率均超过70％。     

Syntheses of (R)- and (S)-2- and 6-fluoronorepinephrine and (R)- and (S)-2- and 6-fluoroepinephrine: effect of stereochemistry on fluorine-induced adrenergic selectivities

Several routes to the enantiomers of fluoronorepinephrines (1) and fluoroepinephrines (2) were explored. A catalytic enantioselective oxazaborolidine reduction and a chiral (salen)Ti(IV) catalyzed asymmetric synthesis of silyl cyanohydrins proved efficacious in the key stereo-defining steps of two respective routes. Binding studies of the catecholamines with alpha(1)-, alpha(2)-, beta(1)-, and beta(2)-adrenergic receptors were examined. The assays confirmed that fluorine substitution had marked effects on the affinity of (R)-norepinephrine and (R)-epinephrine for adrenergic receptors, depending on the position of substitution. Thus, a fluoro substituent at the 2-position of (R)-norepinephrine and (R)-epinephrine reduced activity at both alpha(1)- and alpha(2)-receptors and enhanced activity at beta(1)- and beta(2)-receptors, while fluorination at the 6-position reduced activity at the beta(1)- and beta(2)-receptors. The effects of fluorine substitution on the S-isomers were less predictable.     

Motor hypoactivity induced by neurotensin and related peptides in mice

The tridecapeptide neurotensin (NT) induces a variety of behavioral changes in animals. The present study characterizes the behavioral hypoactivity observed after intracerebroventricular (ICV) injection in mice. At doses higher than 25 ng, NT induced a reduction of general motor activity and increases in immobility which lasted for about one hour. The NT-related amphibian skin peptide xenopsin was about 70-fold more potent than NT itself. After repeated NT-injections, tolerance developed within 2-4 days and disappeared within 2-4 days after cessation of the treatment. The motor hypoactivity induced by NT was not attenuated by pretreatment with naloxone (5 mg/kg, SC). Furthermore, amphetamine-induced locomotor activity was not blocked by NT or xenopsin. These results suggest that the NT-effect is not mediated by a stimulation of opioid mechanisms or attenuation of dopamine-mediated events.     

Comparative disposition of (R)-(+)-pulegone in B6C3F1 mice and F344 rats.

Pulegone is a monoterpene ketone that is usually associated with the herb pennyroyal but is also found in the essential oils from many other mint species. It is the major constituent of pennyroyal oil. Pennyroyal is used as a flavoring and fragrance and as an herbal medicine to induce menstruation and abortion. A disposition study of 14C-pulegone in B6C3F1 mice and F344 rats has been conducted at doses from 0.8 to 80 mg/kg. Mice excrete 85 to 100% of the dose in 24 h. Rats excrete only 59 to 81% of the administered radioactivity in the same time, primarily in urine and feces, with a trace in respired air. Consequently, tissue concentrations are lower in mice than in rats. Male rats tend to have higher tissue concentrations, especially in kidney, than female rats have, but this sex difference is not seen in mice. The residual radioactivity at 24 h demonstrates potential for accumulation of pulegone-derived material in several tissues following multiple doses. The metabolic profile is complex in both species, with at least three pathways involving hydroxylation, reduction, or conjugation with glutathione as first steps. Mercapturic acid pathway metabolites were detected in bile in mice and both bile and urine in rats.     

Metabolism of (-)-6(S)-hydroxy-4(R)-(1-hydroxy-1-methylethyl)-1- cyclohexene-1-ethanol in rat and dog.

1. The metabolism of a new mucoactive drug, chemically (-)-6(S)-hydroxy-4(R)- (1-hydroxy-1-methylethyl)-1-cyclohexene-1-ethanol (CO/1408), has been studied in rat and dog after a single oral dose; eight metabolites were identified. 2. Oxidation of the primary and secondary alcohol groups, hydroxylation in allylic positions and conjugation with glucuronic acid occurred in both species. Products of oxidation on the double bond have not been identified. 3. Using reversed-phase h.p.l.c. and beta-cyclodextrin in the eluent it was found that the glucuronide metabolites varied with species and with the biological fluid examined.     

(R)- and (S)-5,6,7,8-tetrahydro-1-hydroxy-N,N-dipropyl-9H-benzocyclohepten- 8-ylamine. Stereoselective interactions with 5-HT1A receptors in the brain

The enantiomers of 5,6,7,8-tetrahydro-1-hydroxy-N,N-dipropyl-9H-benzocyclohepten-8-++ +ylamine (3) have been synthesized and evaluated for central 5-hydroxytryptamine (5-HT) and dopamine (DA) receptor activity by use of behavioral and biochemical tests in rats. In addition, the ability of the compounds to displace [3H]-8-OH-DPAT from 5-HT1A binding sites was evaluated. The absolute configuration of the enantiomers of 3 was determined indirectly by X-ray diffraction of (+)-(8R,alpha R)-5,6,7,8-tetrahydro-1-methoxy-N-(alpha-phenethyl)-9H- benzocyclohepten-8-ylamine hydrochloride (9.HCl), a resolved synthetic precursor. The stereoselectivity of the interaction of 3 with 5-HT1A receptors was more pronounced than that of 8-hydroxy-2-(dipropylamino)tetralin (1; 8-OH-DPAT); only (R)-3 displayed 5-HT activity. However, (R)-3 was of lower potency than any of the enantiomers of 1. The enantiomer (S)-3, which was found to be inactive as a 5-HT-receptor agonist, appeared to be a weakly potent DA-receptor agonist whereas (R)-3 seemed to be devoid of dopaminergic activity. The conformational preferences of 3 were studied by use of NMR spectroscopy and molecular mechanics calculations. Preferred conformations of (R)-3 are similar in shape to those of the stereoselective 5-HT1A-receptor agonist (2R,3S)-8-hydroxy-3-methyl-2-(dipropylamino)tetralin.     

2-羟甲基-青霉烯-3-羧酸对硝基苄酯的制备

目的研究(5R,6S)-2-羟甲基-6-[(1R)-1-叔丁基-2-二甲基硅氧乙基]-青霉烯-3-羧酸对硝基苄酯的合成方法.方法以商品化的小四环为原料,经噻酸亲核取代、与对硝基苄基草酰氯反应、与亚磷酸三乙酯反应、加热环合、脱去保护基生成目标化合物1.结果与结论设计的合成路线经4步反应,总收率为23%,合成路线简便易行,适宜大规模生产.所合成的中间体及目标产物经核磁共振氢谱确证.     

Clonidine-induced antinociception and locomotor hypoactivity are reduced by dexamethasone in mice

The effects of dexamethasone pretreatment on clonidine-induced antinociception and locomotor hypoactivity were investigated in mice. In the hot-plate and the tail-flick tests, dexamethasone administered intraperitoneally at a dose of 1 mg kg(-1), 30 or 60 min before clonidine, reduced clonidine antinociception in both tests and reduced clonidine-induced locomotor hypoactivity in the activity cage. When administered 15 min before clonidine, dexamethasone had no effect on clonidine antinociception. A higher dexamethasone dose (10 mg kg(-1)) induced the same effects observed at a dose of 1 mg kg(-1) in the hot-plate and the tail-flick tests, but the former dose had a stronger effect on locomotor hypoactivity. Dexamethasone (10 ng/mouse) administered intracerebroventricularly 30 min before clonidine was also able to reduce both clonidine-induced antinociception and locomotor hypoactivity. The protein synthesis inhibitor, cycloheximide, administered intraperitoneally at the dose of 10 mg kg(-1), 2 h before clonidine, was able to prevent dexamethasone effects on clonidine-induced antinociception. The glucocorticoid receptor antagonist RU-38486, administered intracerebroventricularly at the dose of 1 ng/mouse, was also able to block dexamethasone effects on clonidine-induced antinociception and locomotor hypoactivity, whereas both cycloheximide and RU-38486 per se did not influence pain sensitivity or locomotor activity. These results suggest that the dexamethasone effects on clonidine-induced antinociception and locomotor hypoactivity depend on the stimulating effects that dexamethasone exert, on the protein synthesis via the glucocorticoid receptor in the brain.     

The metabolism of (R)-(-)-amphetamine by rabbit liver microsomes. Initial products

The metabolism of 1-amphetamine in rabbit liver is complex in that several routes may give rise to the same intermediate. In this study, the subsequent metabolism of the primary products of N- and C-oxidation were blocked by selecting appropriate incubation conditions. The resulting simplified system was used to investigate the enzymes involved in the two pathways. Phenobarbital treatment increased N- and C-hydroxylation, whereas 3-methylcholanthrene treatment had an inhibitory effect on both pathways. Inhibitors of cytochrome P-450 were either nonselective or were partially selective in inhibiting the two routes of amphetamine metabolism. Induction modulated the sensitivity toward the inhibitors of N- and C-oxidation.     

GC法测定（1R，2R）-（-）-1，2-环己二胺中S，S对映异构体

目的：建立GC法,测定（1R,2R）-（-）-1,2-环己二胺中S,S对映异构体。方法：用三氟乙酸酐对1,2-环己二胺进行柱前衍生化。色谱柱：CHIRALDEX^TM B-DP二丙酰化B-环糊精手性毛细管柱（30m×0．25mm）,检测器：FID,进样口及检测器温度：200℃,柱温：175℃,载气：氮气,流速：3．0mL·min^-1,分流比：50：1,进样量：1．0μL。结果：1,2-环己二胺的R,R与S,S对映异构体衍生物达到基线分离;S,S对映异构体定量限和检测限分别为2．2和0．66mg·L^-1,平均回收率为96．2％,RSD为2．1％（n=6）。结论：本法能较为准确、快速、有效地分离测定（1R,2R）-（-）-1,2-环己二胺中S,S对映异构体。     

Potential anticancer agents: 5-(N-substituted-aminocarbonyl)- and 5-(N-substituted-aminothiocarbonyl)-5,6,7,8-tetrahydrofolic acids

5-[[N-[(Ethoxycarbonyl)alkyl]amino]carbonyl] (6-9) and the corresponding aminothiocarbonyl (12-15) derivatives of 5,6,7,8-tetrahydrofolic acid were prepared as multisubstrate analogues of the substrate--cofactor adduct in the reactions catalyzed by the folate-mediated one-carbon transfer reactions. Evaluation in vitro showed that 7 (alkyl = hexyl) was cytotoxic to H.Ep.-2 cells (ED50, 4 microM) but noncytotoxic to proliferating L1210 cells. No activity was observed for 7 against the P388 leukemia in mice.     

Antinociceptive activity of (-)-(2S,6S)-(6-ethyl-tetrahydropyran-2-yl)-formic acid on acute pain in mice

Pain is a major cause of distress, both physical and psychological. There is a continuous search for new pharmacologically active analgesic agents with minor adverse effects. Recently, the synthesis of (-)-(2S,6S)-(6-ethyl-tetrahydropyran-2-yl)-formic acid [tetrahydropyran derivative (TD)] was described. The objective of this study was to investigate antinociceptive effects of TD. Its activity was compared with the activity of morphine. The effects of TD and morphine were evaluated in models of inflammatory and noninflammatory pain. TD (6-1200 μmol/kg, intraperitoneally) significantly reduced the nociceptive effects induced by acetic acid or formalin in mice. TD also demonstrated an antinociceptive effect in the tail-flick and hot-plate model. The opioid receptor antagonist, naloxone (at 15 μmol/kg, intraperitoneally), reversed the antinociceptive activity of TD in all the models evaluated. Morphine and TD induced tolerance in mice. However, the onset of tolerance to TD was delayed compared with that induced by morphine. These results indicate that TD develops significant antinociceptive activity and, at least part of its effects seems to be mediated by the opioid system.     

HPLC测定甲磺酸罗哌卡因旋光异构体含量

目的:测定经拆分合成的左旋S-(-)-甲磺酸罗哌卡因中右旋R-(+)-甲磺酸罗哌卡因含量。方法:采用高效液相色谱法测定。色谱条件:Chiral—AGP柱(150 mm×4.0 mm,5 μm),流动相为异丙醇-磷酸盐缓冲液[取1 mol·L-1的磷酸二氢钠7.5 mL,0.5 mol·L-1的磷酸氢二钠溶液28.5 mL,加水稀释到1000 mL,调节pH值至7.2](7:93),柱温:25℃,流速为1.0 mL·min～1。紫外检测器,检测波长220 nm,进样量20μL。结果:甲磺酸罗哌卡因消旋体中左旋体、右旋体的保留时间分别为12.1及17.4 min,左、右旋体的分离度良好。精密度试验的RSD为3.3％。结论:采用本方法可简单、准确地测定甲磺酸罗哌卡因中右旋甲磺酸罗哌卡因的含量。