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PubMed1983

Sulfur analogues of psychotomimetic agents. 2. Analogues of (2,5-dimethoxy-4-methylphenyl)-and (2,5-dimethoxy-4-ethylphenyl)isopropylamine.

The two thio analogues of each of the well-known psychotomimetic drugs DOM [(2,5-dimethoxy-4-methylphenyl)isopropylamine] and DOET [(2,5-dimethoxy-4-ethylphenyl)isopropylamine] have been synthesized and pharmacologically evaluated in man. The 5-thio isomers are more potent as psychotomimetic agents than the 2-thio isomers but still represent a drop of an order of magnitude in potency from the sulfur-free counterparts. The dithio analogue of DOM was synthesized and found to be without central activity at a dosage of approximately 50 times the mean effective dose of DOM.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗

PubMed1990

Characterization of serotonergic receptors mediating contraction of ovine umbilical artery.

Responses to serotonergic agonists were studied in isolated umbilical arteries obtained from fetal lambs within 2 weeks of term. The order of potency of the agonists was determined to be 2,5-dimethoxy-4-methyl-amphetamine (DOM) greater than 5-hydroxytryptamine (5-HT) greater than alpha-methyl-5-HT greater than 1-(3-chlorophenyl) piperazine = m-trifluoromethyl-phenylpiperazine greater than 8-hydroxy-dipropylaminotetralin greater than 2-methyl-5-HT greater than 1-(2-methoxyphenyl) piperazine. Variations in the sensitivity and potency of the agonists results primarily from the variation in the affinity for the 5-HT2 receptor and less so in the efficacy, alpha-Methyl-5-HT was a full agonist compared to 5-HT. The others were partial agonists. The mean KA values for 5-HT and DOM were 4.71 +/- 0.62 x 10(-7) and 0.36 +/- 0.04 x 10(-7) M, respectively. Contractions to 5-HT and DOM were antagonized by ketanserin with pA2 values being 9.4 and 9.1, respectively, suggesting that they act on the same receptor and that their responses are mediated by 5-HT2 receptors. Contractile responses to 8-hydroxy-dipropylaminotetralin, 2-methyl-5-HT and the phenylpiperazines [m-trifluoromethyl-phenylpiperazine and 1-(3-chlorophenyl) piperazine] were also blocked by ketanserin (10(-8) M), indicating that contractions produced by these agonists were mediated by 5-HT2 receptors. No antagonism by MDL 72222 (3-tropanyl-3,5-dichlorobenzoate) of responses to 5-HT indicates that 5-HT3 receptors are not present in this tissue.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗

PubMed1996

A three-lever operant procedure differentiates the stimulus effects of R(-)-MDA from S(+)-MDA.

1-(3,4-Methylenedioxyphenyl)-2-aminopropane (MDA) produces an effect in humans that is somewhat similar to both a hallucinogen and a central stimulant. We have previously shown that R(-)-MDA but not S(+)-MDA produces a stimulus effect in animals similar to that of the hallucinogen 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM), whereas S(+)-MDA but not R(-)-MDA produces a stimulus effect similar to that of the stimulant amphetamine. Others have suggested that the stimulus effects of the two MDA isomers may be much more similar than our results would indicate. To help clarify this issue, we have shown that rats (n = 8) can be trained to discriminate 1.25 mg/kg of R(-)-MDA (ED50 = 0.99 mg/kg) from 1.25 mg/kg of S(+)-MDA (ED50 = 0.80 mg/kg) versus 0.9% saline with use of a three-lever operant procedure. To accomplish this task it was necessary to institute a separation of 4 days between injections of the isomers. In tests of stimulus substitution, the administration of various doses of DOM (ED50 = 0.47 mg/kg), S(+)-DOM (ED50 = 2.23 mg/kg) and mescaline (ED50 = 16.04 mg/kg) produced dose-related responding on the R(-)-MDA-appropriate lever. In contrast, the injection of various doses of S(+)-amphetamine (ED50 = 0.46 mg/kg) and cocaine (ED50 = 6.40 mg/kg) produced dose-related responding on the S(+)-MDA-appropriate lever. The administration of racemic MDA, at twice the isomer training dose, resulted in the animals dividing their responses closely between the R(-)-MDA- and S(+)-MDA-designated levers. In antagonism tests, the serotonin-2 antagonist pirenperone blocked the stimulus effect of 1.25 mg/kg of R(-)-MDA but had no effect on the stimulus effect of 1.25 mg/kg of S(+)-MDA. Taken together, these data support the contention that each optical isomer of MDA can produce a markedly different stimulus effect.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗

PubMed1999

Lack of effect of combined low intensity laser therapy/phototherapy (CLILT) on delayed onset muscle soreness in humans.

BACKGROUND AND OBJECTIVES: This study, which was approved by the University's Ethical committee, was conducted to investigate the effectiveness of Combined Low Intensity Laser Therapy/Phototherapy (CLILT) in alleviating the signs and symptoms of Delayed Onset Muscle Soreness (DOMS) over an 11-day period. STUDY DESIGN/MATERIALS AND METHODS: Thirty-six subjects (18 M: 18 F) were randomly allocated, under strictly controlled double-blind conditions, to one of three experimental conditions: Control, Placebo, and CLILT (660-950 nm; 11 J/cm2; pulsed at 73 Hz). DOMS was induced in a standardised fashion in the non-dominant elbow flexors using repeated eccentric contractions until exhaustion was reached. Subjects returned on five consecutive days, and two days during the following week, for treatment according to group, and assessment of outcome variables including range of motion, pain, and tenderness. RESULTS: While analysis of results using repeated measures and one factor ANOVA with post-hoc tests showed significant changes in all variables over time (P < 0.05) as a result of the induction procedure, there were no significant differences observed between groups. CONCLUSIONS: CLILT failed to show any beneficial treatment effect on DOMS, at least at the parameters used here. These results therefore provide no evidence for the claimed biostimulating effects of such therapy.

Adult↗

PubMed2001

Low intensity monochromatic infrared therapy: a preliminary study of the effects of a novel treatment unit upon experimental muscle soreness.

BACKGROUND AND OBJECTIVE: The current study (for which ethical approval was obtained) sought to assess the effect of low intensity monochromatic infrared therapy (LIMIRT) on experimentally induced delayed onset muscle soreness (DOMS). STUDY DESIGN/MATERIALS AND METHODS: Healthy volunteers were recruited (n = 24, 12M:12F) and randomly allocated under strict double blind conditions to one of three experimental groups (n = 8, 4M:4F): Control, Placebo, or Treatment (840 nm; 3.0 J cm(-2), pulse frequency 1 kHz). DOMS was induced in a standardised manner in the biceps brachii of the nondominant arm. Subjects attended on 5 consecutive days during which the degree of pain and functional impairment was assessed. RESULTS: Analysis of results by using nonparametric Freidman and Kruskal-Wallis H tests (with relevant post hoc tests) revealed significant differences (P < 0.05) between Control and LIMIRT treatment groups for pain and tenderness scores. Despite trends in favour of the Treatment group, analysis failed to show any significant differences between the LIMIRT treatment and Placebo groups for all variables except mechanical pain threshold points 3-6 on day 2. CONCLUSION: The results of the current study suggest that LIMIRT is ineffective in the management of DOMS at the parameters investigated.

Female↗

PubMed2001

Analysis of SOX10 function in neural crest-derived melanocyte development: SOX10-dependent transcriptional control of dopachrome tautomerase.

SOX10 is a high-mobility-group transcription factor that plays a critical role in the development of neural crest-derived melanocytes. At E11.5, mouse embryos homozygous for the Sox10(Dom) mutation entirely lack neural crest-derived cells expressing the lineage marker KIT, MITF, or DCT. Moreover, neural crest cell cultures derived from homozygous embryos do not give rise to pigmented cells. In contrast, in Sox10(Dom) heterozygous embryos, melanoblasts expressing KIT and MITF do occur, albeit in reduced numbers, and pigmented cells eventually develop in nearly normal numbers both in culture and in vivo. Intriguingly, however, Sox10(Dom)/+ melanoblasts transiently lack Dct expression both in culture and in vivo, suggesting that during a critical developmental period SOX10 may serve as a transcriptional activator of Dct. Indeed, we found that SOX10 and DCT colocalized in early melanoblasts and that SOX10 is capable of transactivating the Dct promoter in vitro. Our data suggest that during early melanoblast development SOX10 acts as a critical transactivator of Dct, that MITF, on its own, is insufficient to stimulate Dct expression, and that delayed onset of Dct expression is not deleterious to the melanocyte lineage.

Animals↗

PubMed1994

Plasma levels of gonadal steroids during final oocyte maturation of striped bass, Morone saxatilis L.

Levels of estradiol-17 beta (E2), testosterone (T), 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (DHP), and 17 alpha,20 beta,21-trihydroxy-4-pregnen-3-one (20 beta-S) were measured by radioimmunoassay (RIA) in blood plasma of striped bass undergoing final oocyte maturation (FOM). Females were captured just prior to, or in the early stages of, FOM and induced to complete maturation and ovulation with injected human chorionic gonadotropin, synthetic salmon gonadotropin-releasing hormone analogue (sGnRHa; [D-Arg6-Pro9 NEt]-sGnRH), sGnRHa plus the dopamine receptor antagonist, domperidone (DOM), or OVAPRIM, a commercial preparation of sGnRHa + DOM. Their plasma levels of immunoreactive DHP and 20 beta-S were significantly greater at ovulation relative to the time of hormone injection, whereas the plasma levels of E2 and T were greatest at injection and decreased by ovulation and 24 hr thereafter. Plasma levels of 20 beta-S, but not DHP, were sustained at high levels after ovulation. Fish injected only with DOM did not undergo FOM, its associated changes in plasma steroid levels, or ovulation. In females captured at various natural stages of FOM, plasma levels of 20 beta-S and DHP were low during germinal vesicle migration (GVM), peaked coincident with germinal vesicle breakdown, and then decreased near the time of ovulation. Plasma levels of E2 and T were greatest during GVM and decreased as DHP and 20 beta-S levels increased. Analyses of conjugated versus free plasma steroids showed 64-79% of the various hormones to be in the free fraction. RIA of plasma fractionated by reversed-phase HPLC showed that half of the 20 beta-S immunoreactivity coeluted with 5 beta-pregnan-3 alpha,17,20 beta,21-tetrol, a putative 20 beta-S metabolite with 99.7% cross-reactivity in the 20 beta-S RIA. These results indicate that striped bass follow the typical profile of changing plasma steroid levels seen in other teleosts during FOM, with a clear shift from C18 and C19 steroids to C21 steroids. They suggest that both DHP and 20 beta-S, both potent inducers of striped bass FOM in vitro, may play a role in regulating FOM in this species.

Animals↗

PubMed2005

The magnitude of muscle strain does not influence serial sarcomere number adaptations following eccentric exercise.

It is generally accepted that eccentric exercise, when performed by a muscle that is unaccustomed to that type of contraction, results in a delayed onset of muscle soreness (DOMS). A prolonged exposure to eccentric exercise leads to the disappearance of the signs and symptoms associated with DOMS, which has been referred to as the repeated bout effect (RBE). Although the mechanisms underlying the RBE remain unclear, several mechanisms have been proposed, including the serial sarcomere number addition following exercise induced muscle damage. In the traditional DOMS and RBE protocols, muscle injury has been treated as a global parameter, with muscle force and strain assumed to be uniform throughout the muscle. To assess the effects of muscle-tendon unit strain, fiber strain, torque and injury on serial sarcomere number adaptations, three groups of New Zealand White (NZW) rabbits were subjected to chronic repetitive eccentric exercise bouts of the ankle dorsiflexors for 6 weeks. These eccentric exercise protocols consisted of identical muscle tendon unit (MTU) strain, but other mechanical factors were systematically altered. Following chronic eccentric exercise, serial sarcomere number adaptations were not identical between the three eccentric exercise protocols, and serial sarcomere number adaptations were not uniform across all regions of the muscle. Peak torque and relaxation fiber strain were the best predictors of serial sarcomere number across all three protocols. Therefore, MTU strain does not appear to be the primary cause for sarcomerogenesis, and differential adaptations within the muscle may be explained by the nonuniform architecture of the muscle, resulting in differential local fiber strains.

Adaptation, Physiological↗

PubMed1982

Impaired prolactin responsiveness to dopamine antagonists in acromegaly.

Prolactin (PRL) and growth hormone (GH) secretion have been evaluated in 17 acromegalic patients following acute administration of two dopamine (DA) receptor antagonists, i.e. sulpiride (SULP) and domperidone (DOM). Six patients had persistent hyperprolactinemia. In 8 normoprolactinemic patients, i.m. injection of 100 mg SULP elicited only a slight rise iN plasma PRL, which was strikingly lower than that SULP induced in control subjects. Likewise, an i.v. bolus injection of DOM (4 mg) was barely effective to raise plasma PRL in the 11 normoprolactinemic and the 6 hyperprolactinemic patients. DOM was instead capable of inducing a clear-cut rise in plasma PRL in normoprolactinemic controls and in a group of subjects with puerperal hyperprolactinemia. Neither drug affected GH secretion in acromegalic patients. It is proposed that a defective tuberoinfundibular DA function or, alternatively, a diminished PRL reserve due to a decrease pituitary lactotroph mass may be responsible for the blunted PRL responsiveness of acromegalics. However, standing the paucity of present knowledge on the pituitary PRL secretory pool in acromegalics, neither hypothesis seems capable to account satisfactory for the reported results.

Acromegaly↗

PubMed1986

Effects of sustained hyperprolactinemia induced by chronic treatment with domperidone on central dopaminergic systems in the rat.

Chronic treatment with Domperidone (DOM) had no effect on basal prolactin (PRL) secretion or basal levels of Dopamine (DA) metabolites in basal hypothalamus and striatum as compared with the vehicle treated rats. Animals chronically treated with DOM did not present tolerance to a challenge dose of Haloperidol (HAL) and DOM either measuring PRL secretion or striatal DA metabolite levels. The PRL-induced increase in hypothalamic 3,4-dihydroxyphenylacetic acid (DOPAC) was reduced. These results were accompanied by no change at striatal DA receptors, a slight reduction in density-affinity at hypothalamic DA receptors but clear-cut modification in pituitary DA receptors with the appearance of a high affinity-low capacity binding sites. It can be surmised that sustained hyperprolactinemia may induce tolerance in hypothalamic Tuberoinfundibular (TIDA) neurons involved in the inhibitory control of PRL secretion and a change in the kinetic properties of pituitary DA receptors, but it does not consistently affect the activity of the nigro-striatal DA system.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1981

The behavioral effects of hallucinogens in rats following 5,7-dihydroxytryptamine administration into the medial forebrain bundle.

The hypothesis that 5-hydroxytryptamine (5-HT) neurons and/or receptors are involved in the mechanism of action of hallucinogens is supported by the fact that intraventricular administration of the neurotoxin 5,7-dihydroxytryptamine (5,7-DHT) selectively destroys central 5-HT neurons in the brain and potentiates the behavioral effects of lysergic acid diethylamide (LSD), 2,5-dimethoxy-4-methylamphetamine (DOM) and mescaline. The locus in the brain where this potentiation might occur is not known. In the present experiment, the medial forebrain bundle (MFB) was studied because it is the primary tract containing fibers from the cell bodies in the raphe nuclei to forebrain structures receiving 5-HT input. Male rats received 5,7-DHT (6 micrograms/2 microliter) or vehicle injections bilaterally into the MFB; this procedure caused a significant reduction of 5-HT in the cortex, hippocampus and hypothalamus of lesioned rats, but not in the striatum. Regional dopamine and norepinephrine concentrations were not affected by this treatment. The behavioral effects of the hallucinogens were tested in a situation in which the animals pressed a bar under a fixed ratio-40 (FR-40) schedule of food reinforcement. The disruptive effects of LSD on responding were enhanced in the 5,7-DHT-treated animals, while the effects of DOM were diminished; there was no change in the response to mescaline. These data suggest that, while 5-HT neurons are involved in the behavioral effects of hallucinogens, the precise sites and/or mechanisms of action of LSD, DOM and mescaline may differ.

5,7-Dihydroxytryptamine↗

PubMed1996

Lack of effect of transcutaneous electrical nerve stimulation upon experimentally induced delayed onset muscle soreness in humans.

The aim of the current study, for which ethical approval was obtained, was to assess the hypoalgesic efficacy of transcutaneous electrical nerve stimulation (TENS) upon acute stage (72 h) experimentally induced delayed onset muscle soreness (DOMS). TENS naive subjects (n = 48; 24 male and 24 female) were recruited, screened for relevant pathology and randomly allocated to one of four experimental groups: control, placebo, low TENS (200 microseconds; 4 Hz) or high TENS group (200 microseconds; 110 Hz). DOMS was induced in a standardised fashion in the non-dominant elbow flexors of all subjects by repeated eccentric exercise. Subjects attended on three consecutive days for treatment and measurement of elbow flexion, extension and resting angle (Universal goniometer), Mechanical Pain Threshold/tenderness (algometer) and pain (Visual Analogue Scale (VAS)) on a daily basis, plus McGill Pain Questionnaire on the third day only. Measurements were taken before and after treatment under controlled double blinded conditions. Analysis of results using repeated measures analysis of variance (ANOVA) and post hoc tests showed some inconsistent isolated effects of high TENS (110 Hz) compared to the other conditions upon resting angle and flexion scores; no significant effects were found for any of the other variables. These results provide no convincing evidence for any measurable hypoalgesic effects of TENS upon DOMS-associated pain at the stimulation parameters used here.

Adult↗

PubMed1990

Changes in the responsiveness of prolactin secretion to dopaminergic blockade and TRH stimulation throughout sexual maturation in men.

The pituitary prolactin (PRL) response to domperidone (DOM; a dopaminergic antagonist) and TRH administration in human males during different stages of sexual maturation was investigated. Dopaminergic blockade caused an immediate and significant PRL release in all subjects, regardless of the stage of pubertal development. Even though the mean values of peak PRL levels, magnitude of PRL response (delta PRL) and areas under the PRL curve were not significantly different among the different groups, all these parameters showed a clear tendency to increase in parallel to the stage of pubertal development, as indicated by significant positive correlations between age and pubertal stage of the subjects and the magnitude of their PRL response to DOM (r = 0.661, p less than 0.01 and r = 0.536, p = 0.01, respectively). Significant positive correlations also were found between the serum sex steroid hormone concentrations and the PRL response to dopaminergic blockade (r = 0.774, p = 0.02 and r = 0.554, p = 0.01, respectively). In contrast to these findings, no significant differences or tendencies were detected in the PRL responses to TRH among the different subject groups. The different patterns of PRL response to DOM and TRH throughout male puberty might be due to differences in pituitary thresholds for sex steroids between the dopamine- and TRH-dependent intracellular pools.

Adolescent↗

PubMed2004

Cellular mechanisms of serotonin 5-HT2A receptor-mediated cGMP formation: the essential role of glutamate.

The current study explores the mechanisms by which activation of serotonin(2A) (5-HT(2A)) receptors increase production of cyclic guanosine monophosphate (cGMP) in slices of rat frontal cortex. Contrary to results in cortical slices, stimulation of 5-HT(2A) receptors in cells stably expressing this serotonin receptor did not alter cGMP levels. In cortical slices, stimulation of cGMP formation by 2,5-dimethoxy-4-methylamphetamine (DOM), a 5-HT(2A/2C) receptor agonist, was blocked by tetanus toxin, a substance that prevents vesicular neurotransmitter release. However, this stimulation was not altered by tetrodotoxin, an agent that inhibits depolarization-induced neurotransmitter release. Addition of an N-methyl-d-aspartate (NMDA) receptor antagonist, d-AP-7, but not of an AMPA/kainate receptor antagonist CNQX, completely inhibited DOM-mediated cGMP production in the slices. Combined application of maximally effective concentrations of NMDA and DOM elicited a greater increase in cGMP content than either drug alone. The present study shows that 5-HT(2A) receptors do not directly stimulate cGMP formation, but rather that 5-HT(2A) receptor-mediated cGMP production is dependent on extracellular glutamate activating NMDA receptors. The results indicate that 5-HT(2A) receptor-mediated cGMP production could be at least partially attributed to potentiation of NMDA receptor-mediated cGMP formation.

Animals↗

PubMed2006

Chemical and biological characterization of dissolved organic matter from silver fir and beech forest soils.

Despite a growing attention to the dissolved organic matter (DOM) in terrestrial ecosystems and evidence of the fact that vegetation affects the quality of both undissolved and dissolved organic matter in soil, the role of DOM as a biological indicator is still poorly understood. In this work, the fertility of 59 sites, divided into eight key alliances of the order Fagetalia sylvaticae Pawl., was studied considering chemical and biological parameters such as soil DOM, hormone-like activity, low-molecular-weight (LMW) aliphatic and phenolic acids, and floristic data. Both non-parametric tests and principal component analysis (PCA) revealed differences between silver fir and beech forests and within each type of forest. There were also differences between neutrophilous and acidophilous types. What's more, PCA reveals the dominance of the auxin (IAA)-like activity, and of some phenolic acids in distinguishing the acidophilous beeches (ACI) form the other types, whereas the gibberellin (GA)-like activity is more relevant in neutrophilous conditions such as thermophilous (THE) and mesophilous (MESO) beeches and montane (MO), high montane (HMA), high montane (HMC) silver fir forests. The GA-like activity is also related to the succinic, fumaric, malonic, and l-malic acids in the MO, HMA and HMC silver fir forests. Moreover, the role of LMW aliphatic acids in mobilizing the hormone-like activity, which improves forest growth, is stressed. The growth of seedlings of Picea abies was influenced by the phenolic acid content. At concentrations between 1 and 100 microM, phenylacetic and protocatechuic acids inhibited root growth to the same extent as indoleacetic acid, while p-hydroxybenzoic acid had a stimulating effect comparable to that of gibberellic acid. The aliphatic and phenolic acids appear to be related to plant strategies that influence soil fertility affecting plant growth through rhizodeposition. The role of LMW aliphatic and phenolic acids as molecular markers of ecosystem function is noted.

Abies↗

PubMed2005

Degradability of dissolved soil organic carbon and nitrogen in relation to tree species.

The degradability and chemical characteristics of water-extractable dissolved organic carbon (DOC) and nitrogen (DON) from the humus layer of silver birch (Betula pendula Roth), Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) stands were compared in short-term incubation of soil solutions. For all extracts the degradation of DOC and DON was low (12-17% loss) and increased in the order: birch, spruce and pine. In the humus layer under pine a relatively larger pool of rapidly degrading dissolved soil organic matter (DOM) was indicated by the [3H]thymidine incorporation technique, which measures the availability of DOM to bacteria. The degradation of DOC was explained by a decrease in the hydrophilic fraction. For DON, however, both the hydrophilic and hydrophobic fractions tended to decrease during incubation. No major differences in concentrations of hydrophilic and hydrophobic fractions were detected between tree species. Molecular size distribution of DOC and DON, however, revealed slight initial differences between birch and conifers as well as a change in birch extract during incubation. The depletion of very rapidly degrading fractions (e.g., root exudates and compounds from the litter) may explain the low degradability of DOM in the humus layer under birch.

Analysis of Variance↗

PubMed2005

Serotonergic/glutamatergic interactions: potentiation of phencyclidine-induced stimulus control by citalopram.

Previous investigations in our laboratory have found that the stimulus effects of the hallucinogenic serotonergic agonists DOM and LSD are potentiated by phencyclidine [PCP], a non-competitive NMDA antagonist. Also suggestive of behaviorally significant serotonergic/glutamatergic interactions is our finding that stimulus control by both PCP and LSD is partially antagonized by the mGlu2/3 agonist, LY 379268. These observations coupled with the fact that the stimulus effects of LSD and DOM are potentiated by selective serotonin reuptake inhibitors [SSRIs] led us in the present investigation to test the hypothesis that stimulus control by PCP is potentiated by the SSRI, citalopram. Stimulus control was established with PCP [3.0 mg/kg; 30 min pretreatment time] in a group of 12 rats. A two-lever, fixed ratio 10, positively reinforced task with saline controls was employed. Potentiation by citalopram of an intermediate dose of PCP was observed. In an attempt to establish the mechanism by which citalopram might interact with PCP, subsequent experiments examined the effects on that interaction of antagonists at serotonergic receptors. It was found that the selective 5-HT2C-selective antagonists, SDZ SER 082 and SB 242084, significantly, albeit only partially, blocked the effects of citalopram on PCP. In agreement with our previous conclusions regarding the interaction of citalopram with DOM, the present data suggest that potentiation of the stimulus effects of PCP by citalopram are mediated in part by agonist activity at 5-HT2C receptors.

Aminopyridines↗

PubMed2006

Leachate migration from spent mushroom substrate through intact and repacked subsurface soil columns.

Field weathering of spent mushroom substrate (SMS) produces soluble compost leachate that percolates into underlying soils and may adversely impact groundwater. Laboratory experiments were conducted to investigate movement and retention of SMS leachate solutes in subsurface soil columns. Spent mushroom substrate leachate with high concentrations of dissolved organic matter (DOM) and inorganic salts was passively loaded to intact and repacked columns of Bt1 soil (fine-loamy, mixed, semiactive, mesic Typic Hapludults) and effluents were monitored for changes in chemical composition. Transport of SMS leachate in undisturbed soil cores was mainly via preferential flow, whereas matrix flow was predominant in repacked soil columns. Leachate DOM and phosphate were sorbed by soil minerals while Cl-, SO4(2-), Na+ and NH4+ were eluted. Leachate K+ displaced exchangeable native cations and was retained. Biodegradation of leachate DOM resulted in reduction and elution of soil Mn and Fe, especially in repacked columns. Persistent anoxia also inhibited nitrification. Precipitation of gypsum and CaCO3 blocked preferential flow channels, and movement of SMS leachate was subsequently reduced. The results demonstrate that SMS leachate migrates via rapid preferential flow initially, followed by matrix flow at a lower rate. Leachate solutes may transport to depth in soil profiles through preferential channels. To protect water resources, weathering of deep SMS piles should be conducted on compact surfaces or in fields with a condensed soil layer (no structural cracks) above the groundwater table, and measures controlling leachate runoff be imposed.

Adsorption↗