Hypermagnesemia disturbances in rats,NO-related: pentadecapeptide BPC 157 abrogates, <Emphasis Type="SmallCaps">l</Emphasis>-NAME and <Emphasis Type="SmallCaps">l</Emphasis>-arginine worsen

Aim

Stable gastric pentadecapeptide BPC 157, administered before a high-dose magnesium injection in rats, might be a useful peptide therapy against magnesium toxicity and the magnesium-induced effect on cell depolarization. Moreover, this might be an NO-system-related effect. Previously, BPC 157 counteracts paralysis, arrhythmias and hyperkalaemia, extreme muscle weakness; parasympathetic and neuromuscular blockade; injured muscle healing and interacts with the NOS-blocker and NOS-substrate effects.

Main methods

Assessment included magnesium sulfate (560 mg/kg intraperitoneally)-induced muscle weakness, muscle and brain lesions, hypermagnesemia, hyperkalaemia, increased serum enzyme values assessed in rats during and at the end of a 30-min period and medication (given intraperitoneally/kg at 15 min before magnesium) [BPC 157 (10 µg, 10 ng), l-NAME (5 mg), l-arginine (100 mg), alone and/or together]. In HEK293 cells, the increasing magnesium concentration from 1 to 5 mM could depolarize the cells at 1.75 ± 0.44 mV.

Key findings

l-NAME + magnesium-rats and l-arginine + magnesium-rats exhibited worsened severe muscle weakness and lesions, brain lesions, hypermagnesemia and serum enzymes values, with emerging hyperkalaemia. However, l-NAME + l-arginine + magnesium-rats exhibited all control values and normokalaemia. BPC 157 abrogated hypermagnesemia and counteracted all of the magnesium-induced disturbances (including those aggravated by l-NAME or l-arginine). Thus, cell depolarization due to increasing magnesium concentration was inhibited in the presence of BPC 157 (1 µM) in vitro.

Significance

BPC 157 likely counteracts the initial event leading to hypermagnesemia and the life-threatening actions after a magnesium overdose. In contrast, a worsened clinical course, higher hypermagnesemia, and emerging hyperkalaemia might cause both l-NAME and l-arginine to affect the same events adversely. These events were also opposed by BPC 157.

     

Cyclophosphamide induced stomach and duodenal lesions as a NO-system disturbance in rats: <Emphasis Type="SmallCaps">l</Emphasis>-NAME, <Emphasis Type="SmallCaps">l</Emphasis>-arginine,stable gastric pentadecapeptide BPC 157

We revealed a new point with cyclophosphamide (150 mg/kg/day intraperitoneally for 7 days): we counteracted both rat stomach and duodenal ulcers and increased NO- and MDA-levels in these tissues. As a NO-system effect, BPC 157 therapy (10 µg/kg, 10 ng/kg, intraperitoneally once a day or in drinking water, till the sacrifice) attenuated the increased NO- and MDA-levels and nullified, in rats, severe cyclophosphamide-ulcers and even stronger stomach and duodenal lesions after cyclophosphamide + l-NAME (5 mg/kg intraperitoneally once a day). l-arginine (100 mg/kg intraperitoneally once a day not effective alone) led l-NAME-values only to the control values (cyclophosphamide + l-NAME + l-arginine-rats). Briefly, rats were sacrificed at 24 h after last administration on days 1, 2, 3, or 7, and assessment included sum of longest lesions diameters (mm) in the stomach and duodenum, oxidative stress by quantifying thiobarbituric acid reactivity as malondialdehyde equivalents (MDA), NO in stomach and duodenal tissue samples using the Griess reaction. All these parameters were highly exaggerated in rats who underwent cyclophosphamide treatment. We identified high MDA-tissue values, high NO-tissue values, ulcerogenic and beneficial potential in cyclophosphamide-l-NAME-l-arginine-BPC 157 relationships. This suggests that in cyclophosphamide damaged rats, NO excessive release generated by the inducible isozyme, damages the vascular wall and other tissue cells, especially in combination with reactive oxygen intermediates, while failing endothelial production and resulting in further aggravation by l-NAME which was inhibited by l-arginine. Finally, BPC 157, due to its special relations with NO-system, may both lessen increased MDA- and NO-tissues values and counteract effects of both cyclophosphamide and l-NAME on stomach and duodenal lesions.     

Inhibitory effects of MPEP,an mGluR5 antagonist,and memantine,an <Emphasis Type="Italic">N</Emphasis>-methyl-<Emphasis Type="SmallCaps">D</Emphasis>-aspartate receptor antagonist,on morphine antinociceptive tolerance in mice

Abstract Rationale. Inhibition of N-methyl-D-aspartate (NMDA) receptors by memantine, an NMDA-receptor antagonist, and other antagonists of ionotropic receptors for glutamate inhibit the development of opiate antinociceptive tolerance. The role of metabotropic receptors for glutamate (mGluR) in opiate tolerance is less known. Objective. In the present study, we examined the effect of 2-methyl-6-(phenylethynyl)-pyridine (MPEP), the mGluR type-I (subtype mGluR5) antagonist, as well as the effect of co-administration of low doses of memantine and MPEP on morphine antinociceptive tolerance in mice. Methods. Morphine antinociceptive activity was tested twice, before and after chronic morphine administration, in the tail-flick test using a cumulative dose–response protocol. Tolerance was induced by six consecutive days of b.i.d. administration of morphine (10 mg/kg, s.c.). Saline, memantine (7.5 mg/kg and 2.5 mg/kg, s.c.), MPEP (30 mg/kg and 10 mg/kg, i.p.) and the combination of both antagonists at low doses was given 30 min prior to each morphine injection during its chronic administration. A separate experiment assessed the effects of memantine, MPEP and their combination on acute morphine antinociception using a tail-flick test. Results. MPEP (30 mg/kg but not 10 mg/kg) as well as memantine (7.5 mg/kg but not 2.5 mg/kg) attenuated the development of tolerance to morphine-induced antinociception. When given together, the low doses of MPEP (10 mg/kg) and memantine (2.5 mg/kg) also significantly attenuated opiate tolerance. None of the treatments with glutamate antagonists produced antinociceptive effects or significantly affected morphine-induced antinociception. Conclusions. The data suggest that both mGluR5 and NMDA receptors may be involved in the development of morphine antinociceptive tolerance. Electronic Publication     

Class side effects: decreased pressure in the lower oesophageal and the pyloric sphincters after the administration of dopamine antagonists,neuroleptics, anti-emetics, <Emphasis Type="SmallCaps">l</Emphasis>-NAME,pentadecapeptide BPC 157 and <Emphasis Type="SmallCaps">l</Emphasis>-arginine

The ulcerogenic potential of dopamine antagonists and l-NAME in rats provides unresolved issues of anti-emetic neuroleptic application in both patients and experimental studies. Therefore, in a 1-week study, we examined the pressures within the lower oesophageal and the pyloric sphincters in rats [assessed manometrically (cm H₂O)] after dopamine neuroleptics/prokinetics, l-NAME, l-arginine and stable gastric pentadecapeptide BPC 157 were administered alone and/or in combination. Medication (/kg) was given once daily intraperitoneally throughout the 7 days, with the last dose at 24 h before pressure assessment. Given as individual agents to healthy rats, all dopamine antagonists (central [haloperidol (6.25 mg, 16 mg, 25 mg), fluphenazine (5 mg), levomepromazine (50 mg), chlorpromazine (10 mg), quetiapine (10 mg), olanzapine (5 mg), clozapine (100 mg), sulpiride (160 mg), metoclopramide (25 mg)) and peripheral(domperidone (10 mg)], l-NAME (5 mg) and l-arginine (100 mg) decreased the pressure within both sphincters. As a common effect, this decreased pressure was rescued, dose-dependently, by BPC 157 (10 µg, 10 ng) (also note that l-arginine and l-NAME given together antagonized each other’s responses). With haloperidol, l-NAME worsened both the lower oesophageal and the pyloric sphincter pressure, while l-arginine ameliorated lower oesophageal sphincter but not pyloric sphincter pressure, and antagonized l-NAME effect. With domperidone, l-arginine originally had no effect, while l-NAME worsened pyloric sphincter pressure. This effect was opposed by l-arginine. All these effects were further reversed towards a stronger beneficial effect, close to normal pressure values, by the addition of BPC 157. In addition, NO level was determined in plasma, sphincters and brain tissue. Thiobarbituric acid reactive substances (TBARS) were also assessed. Haloperidol increased NO levels (in both sphincters, the plasma and brain), consistently producing increased TBARS levels in the plasma, sphincters and brain tissues. These effects were all counteracted by BPC 157 administration. In conclusion, we revealed that BPC 157 counteracts the anti-emetic neuroleptic class side effect of decreased pressure in sphincters and the dopamine/NO-system/BPC 157 relationship.     

Effect of tiron on remote organ injury in rats with severe acute pancreatitis induced by <Emphasis Type="SmallCaps">l</Emphasis>-arginine

Acute pancreatitis (AP) is an acute inflammatory disorder of the pancreas that can be complicated by involvement of other remote organs. Oxidative stress is known to have a crucial role in the development of pancreatic acinar damage and one of the main causes in multisystem organ failure in experimental AP. The aim of the study was to determine the effect of tiron on pancreas and remote organ damage in l-arginine (L-Arg) induced AP rat model. Thirty-two male rats were divided in random into four groups: control, tiron, L-Arg, and tiron with L-Arg. At the end of the experiment, blood samples were withdrawn for biochemical analysis. The pancreas, lung, kidney, and liver were collected for histopathological examination. Estimation of pancreatic water content was done. Analysis of pulmonary, hepatic, renal, and pancreatic lipid peroxide levels (MDA), superoxide dismutase (SOD), and reduced glutathione (GSH) were carried out. Finally, nuclear factor kappa B (NF-κB) and transforming growth factor β1 (TGF-β1) expression in pancreatic tissue was determined. Results indicated that treatment with tiron significantly decreased lipid peroxide levels and markedly increased both SOD activity and GSH level. Moreover, histopathological analysis further confirmed that administration of tiron relatively ameliorates pancreatic acinar cells and remote organ damage. Increased immunoreactivity of NF-κB and TGF-β1 were reduced also by tiron treatment. These findings pointed out the protective role of the mitochondrial antioxidant, tiron against AP induced by L-Arg.     

The amino acid <Emphasis Type="SmallCaps">l</Emphasis>-lysine blocks the disruptive effect of phencyclidine on prepulse inhibition in mice

Rationale The cognitive and attentional deficits observed in schizophrenic patients are now considered central to the pathophysiology of the disorder. These deficits include an inability to filter sensory input as measured by, e.g., prepulse inhibition (PPI) reflex. Administration of phencyclidine (PCP), a drug that can induce a schizophrenia-like psychosis in humans, disrupts PPI in experimental animals. In rodents, this PCP-induced deficit can be blocked by pretreatment with nitric oxide (NO) synthase inhibitors. This suggests that some of the behavioral effects of PCP are mediated via NO. The substrate for in vivo NO production is l-arginine, and active transport of l-arginine via the cationic amino acid transporter may serve as a regulatory mechanism in NO production. Objectives The aim of the present study was to study the effects of l-arginine transport inhibition, using acute and repeated l-lysine treatment, on PCP-induced disruption of PPI in mice. Results Subchronic, and to some extent acute, pretreatment with l-lysine blocked a PCP-induced deficit in PPI without affecting basal PPI. Conclusions l-lysine has been shown to block l-arginine transport in vitro, most likely via a competitive blockade and down regulation of cationic amino acid transporters. However, the importance of l-arginine transport as a regulatory mechanism in NO production in vivo is still not clear. The present results lend further support to the notion that some of the effects of PCP in the central nervous system are mediated via NO and that l-arginine transport may play a role in the regulation of NO production in the brain.     

Discriminative stimulus and reinforcing effects of <Emphasis Type="Italic">p</Emphasis>-fluoro-<Emphasis Type="SmallCaps">l</Emphasis>-deprenyl in monkeys

Rationale para-Fluoro-l-deprenyl (Fludepryl), a halogenated derivative of l-deprenyl, shares structural similarities with amphetamine and may have potential as a medication for psychostimulant abuse. Objectives p-Fluoro-l-deprenyl was evaluated for psychomotor stimulant, discriminative stimulus, and reinforcing effects in squirrel monkeys. Methods One group of monkeys was trained under a ten-response fixed-ratio (FR10) schedule of stimulus termination to discriminate between methamphetamine (0.32 mg/kg, i.m.) and saline. Other monkeys were trained to self-administer i.v. cocaine under either a simple FR10 schedule or a second-order fixed-interval 5-min schedule with FR10 components. Results Full generalization to the methamphetamine-training stimulus was produced by an i.m. dose of 10.0 mg/kg p-fluoro-l-deprenyl. l-Deprenyl and the metabolites of p-fluoro-l-deprenyl, p-fluoro-l-amphetamine, and p-fluoro-l-methylamphetamine were more potent, producing full generalization at doses of 1.0–3.2 mg/kg. Under the FR10 schedule of drug injection, persistent self-administration behavior was maintained by i.v. cocaine injections but not by injections of vehicle or injection doses of p-fluoro-l-deprenyl up to 1.0 mg/kg. However, p-fluoro-l-deprenyl did maintain moderate levels of i.v. self-administration responding under the second-order schedule of drug injection. Peak response rates maintained by 0.1-mg/kg injections of p-fluoro-l-deprenyl were significantly greater than those associated with saline substitution, yet significantly lower than those maintained by cocaine or d-amphetamine. Conclusions p-Fluoro-l-deprenyl has methamphetamine-like discriminative-stimulus properties in squirrel monkeys that appear at higher doses than for its parent compound, l-deprenyl. It also appears to function as a relatively limited reinforcer of intravenous self-administration behavior in monkeys trained to self-administer i.v. cocaine.     

NMDA receptor modulation by <Emphasis Type="SmallCaps">d</Emphasis>-cycloserine promotes episodic-like memory in mice

Rationale NMDA-R (N-methyl-d-aspartate receptors) have been implicated in synaptic plasticity underlying one-trial learning of event-place associations. In rodents, episodic-like memory (ELM) of personally experienced events can be inferred from behavior that reflects the remembrance of the content (what kind of object was presented), place (where was this object placed), and temporal context (when was the object presented). We have previously shown that that d-cycloserine (DCS), an NMDA-R agonist, ameliorates stress-induced deficits in ELM. Objectives In this study, we used an experimental protocol designed to detect promnestic drug effects and investigated whether DCS, which is known to enhance learning and memory, can induce ELM under conditions where mice normally do not show ELM. Results Mice that have been treated i.p. with DCS (20 mg/kg) both remembered the temporal order in which two different objects had been encountered during two consecutive sample trials, as well as their spatial position during the sample trials. Most importantly, the test trial performance of these mice is compatible with ELM in terms of an integrated memory for unique experiences comprising “what”, “where”, and “when” information. In contrast, mice that have received either a saline injection or lower doses of DCS (0.2 and 2.0 mg/kg) did not show such an integrated ELM. Conclusions To our knowledge, this is the first report showing that DCS can promote ELM in mice.     

Behavioral and molecular evidence for psychotropic effects in <Emphasis Type="SmallCaps">l</Emphasis>-theanine

Rationale  

l-Theanine (N-ethyl-l-glutamine) is an amino acid uniquely found in green tea and historically considered to be a relaxing agent. It is a glutamate derivative and has an affinity for glutamatergic receptors. However, its psychotropic effects remain unclear.     

The effect of <Emphasis Type="Italic">d</Emphasis>,<Emphasis Type="Italic">l</Emphasis>-methamphetamine on simulated driving performance

Rationale  

Illicit drugs such as methamphetamine are commonly abused drugs that have also been observed to be prevalent in drivers injured in road accidents. The exact effect of methamphetamine or its specific isomers on driving and driving behaviour have yet to be thoroughly investigated.     

Excitatory regulation of noradrenergic neurons by <Emphasis Type="SmallCaps">l</Emphasis>-arginine/nitric oxide pathway in the rat locus coeruleus in vivo

To elucidate conflicting findings about the role of l-arginine/nitric oxide (NO) pathway in the locus coeruleus (LC), we investigated the effects of different drugs affecting NO concentrations by single-unit extracellular recordings from LC neurons in vivo and in vitro. In anesthetized rats, central (3.8–15.3 nmol i.c.v.) and local (16.5–66 pmol into the LC) administrations of the NO donor sodium nitroprusside, but not those of the inactive analogue potassium ferricyanide (16.5–66 pmol into the LC), increased by 65–84% the firing rate of LC neurons. In brain slices, low concentrations (50–200 μM) of diethylamine/NO complex, a short-lived NO releaser, also increased the neuron firing rate, although higher drug concentrations (400–800 μM) caused slowly reversible reductions of the firing activity. On the other hand, the NO synthase inhibitors N^ω-nitro-l-arginine methyl ester (l-NAME) (148–371 nmol i.c.v.) and N^ω-nitro-l-arginine (l-NA) (46 nmol i.c.v.) gradually decreased the firing rate of LC neurons, whereas the NO synthase substrate l-arginine (0.71–1.42 μmol i.c.v. and 0.6–4.8 nmol into the LC) increased the neuron activity. The latter effect was not mimicked by the vehicle or the less active isomer d-arginine (0.6–4.8 nmol into the LC). Unexpectedly, pretreatment with high concentrations of l-NAME (371 nmol and 18.5 μmol i.c.v.) or l-NA (45.6 nmol i.c.v. and 0.24 nmol into the LC) failed to block the effect of l-arginine. The glutamate receptor antagonist kynurenic acid (1 μmol i.c.v.) strongly reduced the effect of l-arginine but not that of sodium nitroprusside. These data confirm in vivo a direct excitatory effect of NO on LC neurons and suggest a tonic regulation of noradrenergic neurons by NO in vivo. l-arginine also excites LC neurons, but this effect may be caused by a nitric-oxide-unrelated glutamate-receptor-mediated mechanism.     

Buspirone-induced antinociception is mediated by <Emphasis Type="SmallCaps">l</Emphasis>-type calcium channels and calcium/caffeine-sensitive pools in mice

Rationale. Previous studies have shown that buspirone, a partial 5-HT_1A receptor agonist, produces antinociceptive effects in rats and mice; Ca²⁺ plays a critical role as a second messenger in mediating nociceptive transmission. 5-HT_1A receptors have been proven to be coupled functionally with various types of Ca²⁺ channels in neurons, including N-, P/Q-, T-, or L-type. It was of interest to investigate the involvement of extracellular/intracellular Ca²⁺ in buspirone-induced antinociception. Objectives. To determine whether central serotonergic pathways participate in the antinociceptive processes of buspirone, and investigate the involvement of Ca²⁺ mechanisms, particularly L-voltage-gated Ca²⁺ channels and Ca²⁺/caffeine-sensitive pools, in buspirone-induced antinociception. Methods. Antinociception was assessed using the hot-plate test (55°C, hind-paw licking latency) in mice treated with either buspirone (1.25–20 mg/kg i.p.) alone or the combination of buspirone and fluoxetine (2.5–10 mg/kg i.p.), 5-HTP (25 mg/kg i.p.), nimodipine (2.5–10 mg/kg i.p.), nifedipine (2.5–10 mg/kg i.p.), CaCl₂ (25–200 nmol per mouse i.c.v.), EGTA (5–30 nmol per mouse i.c.v.), or ryanodine (0.25–2 nmol per mouse i.c.v.). Results. Buspirone dose dependently increased the licking latency in the hot-plate test in mice. This effect of buspirone was enhanced by fluoxetine, 5-HTP, nimodipine, and nifedipine. Interestingly, central administration of Ca²⁺ reversed the antinociceptive effects of buspirone. In contrast to these, ryanodine or EGTA administered centrally potentiated buspirone-induced antinociception. Conclusions. Decreasing neuronal Ca²⁺ levels potentiated buspirone-induced antinociception; conversely, increasing intracellular Ca²⁺ abolished the antinociceptive effects of buspirone. These results suggest that Ca²⁺ influx from extracellular fluid and release of Ca²⁺ from Ca²⁺/caffeine-sensitive microsomal pools may be involved in buspirone-induced antinociception. Electronic Publication     

Effects of low-dose <Emphasis Type="SmallCaps">d</Emphasis>-serine on recognition and working memory in mice

Rationale  

d-Serine is an endogenous co-agonist of the N-methyl-d-aspartate (NMDA) receptor and has been suggested to improve cognitive deficits in schizophrenia.     

Elevated prolactin responses to <Emphasis Type="SmallCaps">l</Emphasis>-tryptophan infusion in medication-free depressed patients

Rationale Several previous neuroendocrine studies have demonstrated reduced 5-HT_1A receptor function in major depressive disorder (MDD). However, hypercortisolaemia or previous drug treatment may have been significant confounds. Objectives To replicate previous studies in subjects with MDD who had been drug free for at least 8 weeks and to relate the findings to measures of HPA axis function. Methods Hormonal responses to l-tryptophan infusion were measured in patients with MDD (n=20) and healthy controls (n=20). Basal salivary cortisol and DHEA were also profiled. Results No attenuation of 5-HT_1A receptor-dependent neuroendocrine responses (growth hormone, prolactin) was observed in patients with MDD. The prolactin response to l-tryptophan was significantly greater in MDD patients than in healthy controls (P=0.008). There was a significant negative correlation between prolactin response and basal salivary cortisol secretion over the 3 days prior to the test. Conclusions These data do not support previous findings of reduced 5-HT_1A function in MDD and suggest that hypercortisolaemia or psychotropic medication may have accounted for the attenuation. Basal cortisol, DHEA and the cortisol-DHEA ratio did not differ between patients and controls, and all patients were psychotropic medication-free. The greater prolactin response to l-tryptophan infusion in depressed subjects may be the result of an increase in dopamine receptor sensitivity, secondary to reduced dopamine levels.     

Glycine and <Emphasis Type="SmallCaps">d</Emphasis>-serine,but not <Emphasis Type="SmallCaps">d</Emphasis>-cycloserine,attenuate prepulse inhibition deficits induced by NMDA receptor antagonist MK-801

RATIONALE: Several agents that stimulate the glycine site of N-methyl-D: -aspartate (NMDA) receptors have been reported to moderately improve both negative symptoms and cognitive dysfunctions in patients with schizophrenia. However, differences in efficacy have also been reported, and further comparative pharmacological studies are still needed. OBJECTIVES: We aimed to explore the effects of two glycine site agonists of the NMDA receptor, glycine and D: -serine, and a partial agonist, D: -cycloserine, on prepulse inhibition (PPI) deficits induced by a NMDA receptor antagonist, MK-801, in mice. Furthermore, we performed in vivo microdialysis and additional PPI measurements using a selective glycine site antagonist to verify if the beneficial effects observed after the systemic administration of glycine were due to glycine itself via its activity at the glycine site. RESULTS: High doses of glycine (1.6 g/kg) and D: -serine (1.8 and 2.7 g/kg) significantly attenuated MK-801-induced PPI deficits. In contrast, D: -cycloserine did not show any amelioration of MK-801-induced PPI deficits at doses ranging from 7.5 mg/kg to 60 mg/kg. The selective glycine site antagonist, L-701,324 (10 mg/kg), antagonized the effect of glycine on MK-801-induced PPI deficits. Furthermore, in vivo microdialysis demonstrated that intraperitoneal injection of glycine significantly increased glycine and L: -serine levels, but decreased D: -serine levels in the prefrontal cortex. CONCLUSIONS: The findings of the present study suggest that glycine and D: -serine but not D: -cycloserine could attenuate PPI deficits associated with NMDA receptor hypofunction via NMDA glycine sites in the brain.     

Investigations on the Humidity-Induced Transformations of Salbutamol Sulphate Particles Coated with <Emphasis Type="SmallCaps">l</Emphasis>-Leucine

PURPOSE: The crystallization and structural integrity of micron-sized inhalable salbutamol sulphate particles coated with L: -leucine by different methods are investigated at different humidities. The influence of the L: -leucine coating on the crystallization of salbutamol sulphate beneath the coating layer is explored. METHODS: The coated particles are prepared by an aerosol flow reactor method, the formation of the L: -leucine coating being controlled by the saturation conditions of the L: -leucine. The coating is formed by solute diffusion within a droplet and/or by vapour deposition of L: -leucine. The powders are humidified at 0%, 44%, 65% and 75% of relative humidity and the changes in physical properties of the powders are investigated with dynamic vapour sorption analysis (DVS), a differential scanning calorimeter (DSC), and a scanning electron microscope (SEM). RESULTS: Visual observation show that all the coated particles preserve their structural integrity whereas uncoated salbutamol sulphate particles are unstable at 65% of relative humidity. The coating layer formed by diffusion performs best in terms of its physical stability against moisture and moisture-induced crystallization. The degree of crystallization of salbutamol in the as-prepared powders is within the range 24-35%. The maximum degree of crystallization after drying ranges from 55 to 73% when the salbutamol crystallizes with the aid of moisture. In addition to providing protection against moisture, the L: -leucine coating also stabilizes the particle structure against heat at temperatures up to 250 degrees C. CONCLUSION: In order to preserve good flowability together with good physical stability, the best coating would contain two L: -leucine layers, the inner layer being formed by diffusion (physical stability) and the outer layer by vapour deposition (flowability).     

Effects of <Emphasis Type="Italic">Bidens pilosa</Emphasis> L. var. <Emphasis Type="Italic">radiata</Emphasis> S<Emphasis Type="SmallCaps">cherff</Emphasis> on experimental gastric lesion

Bidens pilosa L. var. radiata Scherff (BP) is a plant used as a traditional folk medicine. BP, cultivated with only green manure on Miyako Island, Okinawa prefecture, was processed to powder and is referred to as MMBP. We have reported that MMBP has antioxidant, anti-inflammatory, and anti-allergy properties. In this study, we investigated the effects of MMBP on several experimental gastric lesions induced by HCl/EtOH, a non-steroidal anti-inflammatory drug, or cold-restraint stress, comparing these results with those of rutin or anti-ulcerogenic drugs (cimetidine or sucralfate) based on the lesion index and hemorrhage from the gastric lesions. Orally administered MMBP prevented the progression of the gastric lesions. Moreover, treatment with MMBP, rutin, or sucralfate, which had potent antioxidative activity, inhibited increases in the levels of thiobarbituric acid reactive substances (TBARS) in the gastric mucosal lesions. The inhibition of the gastric mucosal TBARS content by MMBP may have been due to the antioxidant effects of MMBP. These results indicate that MMBP prevents the progression of acute gastric mucosal lesions, possibly by suppressing oxidative stress in the gastric mucosa.     

<Emphasis Type="SmallCaps">l</Emphasis>-Arginine reverses cigarette-induced reduction of fractional exhaled nitric oxide in asthmatic smokers

Introduction  

Complex mechanisms regulate nitric oxide (NO) synthesis. Cigarette smoking decreases fractional exhaled NO (FE_NO), while asthmatic inflammation increases FE_NO. To assess whether the smoking-induced decrease in FE_NO levels was reversible, asthmatic and non-asthmatic smokers inhaled the NO synthase (NOS) substrate, l-arginine. Aminoguanidine, a relatively selective Type II NOS inhibitor, was used also to assess the role of NOS subtypes in these changes of FE_NO.     

Differential effects of the <Emphasis Type="SmallCaps">d-</Emphasis> and <Emphasis Type="SmallCaps">l-</Emphasis> isomers of amphetamine on pharmacological MRI BOLD contrast in the rat

Rationale

The d- and l-amphetamine sulphate isomers are used in the formulation of Adderall XR®, which is effective in the treatment of attention-deficit hyperactivity disorder (ADHD). The effects of these isomers on brain activity has not been examined using neuroimaging.

Objectives

This study determines the pharmacological magnetic resonance imaging blood-oxygenation-level-dependent (BOLD) response in rat brain regions after administration of each isomer.

Materials and methods

Rats were individually placed into a 2.35 T Bruker magnet for 60 min to achieve basal recording of variation in signal intensity. Either saline (n?=?9), d-amphetamine sulphate (2 mg/kg, i.p.; n?=?9) or l-amphetamine sulphate (4 mg/kg, i.p.; n?=?9) were administered, and recording continued for a further 90 min. Data were analysed for BOLD effects using statistical parametric maps. Blood pressure, blood gases and respiratory rate were monitored during scanning.

Results

The isomers show overlapping effects on the BOLD responses in areas including nucleus accumbens, medial entorhinal cortex, colliculi, field CA1 of hippocampus and thalamic nuclei. The l-isomer produced greater global changes in the positive BOLD response than the d-isomer, including the somatosensory and motor cortices and frontal brain regions such as the orbitofrontal cortices, prelimbic and infralimbic cortex which were not observed with the d-isomer.

Conclusions

The amphetamine isomers produce different BOLD responses in brain areas related to cognition, pleasure, pain processing and motor control probably because of variations on brain amine systems such as dopamine and noradrenaline. The isomers may, therefore, have distinct actions on brain regions affected in ADHD patients.

     

Identification of medicinal <Emphasis Type="Italic">Dendrobium</Emphasis> species by phylogenetic analyses using <Emphasis Type="Italic">matK</Emphasis> and <Emphasis Type="Italic">rbcL</Emphasis> sequences

Species identification of five Dendrobium plants was conducted using phylogenetic analysis and the validity of the method was verified. Some Dendrobium plants (Orchidaceae) have been used as herbal medicines but the difficulty in identifying their botanical origin by traditional methods prevented their full modern utilization. Based on the emerging field of molecular systematics as a powerful classification tool, a phylogenetic analysis was conducted using sequences of two plastid genes, the maturase-coding gene (matK) and the large subunit of ribulose 1,5-bisphosphate carboxylase-coding gene (rbcL), as DNA barcodes for species identification of Dendrobium plants. We investigated five medicinal Dendrobium species, Dendrobium fimbriatum, D. moniliforme, D. nobile, D. pulchellum, and D. tosaense. The phylogenetic trees constructed from matK data successfully distinguished each species from each other. On the other hand, rbcL, as a single-locus barcode, offered less species discriminating power than matK, possibly due to its being present with little variation. When results using matK sequences of D. officinale that was deposited in the DNA database were combined, D. officinale and D. tosaense showed a close genetic relationship, which brought us closer to resolving the question of their taxonomic identity. Identification of the plant source as well as the uniformity of the chemical components is critical for the quality control of herbal medicines and it is important that the processed materials be validated. The methods presented here could be applied to the analysis of processed Dendrobium plants and be a promising tool for the identification of botanical origins of crude drugs.