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Abstract Rationale: The triazolobenzodiazepine alprazolam has a unique clinical profile compared to most other benzodiazepines (e.g. diazepam, chlordiazepoxide), in that it is used to treat panic disorder and is effective in depression, two disorders that are usually treated with anti-depressants. Previous drug discrimination studies suggested that alprazolam has stimulus properties in common with antidepressants. Objective: In the present study, the discriminative stimulus properties of alprazolam were investigated to test more conclusively the role of benzodiazepine receptors and whether alprazolam has stimulus properties in common with antidepressants. Methods: Male Wistar rats (n=12) were trained to discriminate between alprazolam (2.0 mg/kg, PO) and vehicle in an operant two-lever drug discrimination procedure under a tandem VI40"-FR10 schedule of reinforcement. Generalization and antagonism tests were carried out under 2 min extinction. Results' In generalization tests, a number of benzodiazepines (alprazolam, chlordiazepoxide, midazolam, lorazepam) and the barbiturate pentobarbital substituted completely, while zolpidem and abecarnil substituted partially for alprazolam. In contrast, no significant degree of generalization to the antidepressants imipramine and fluvoxamine and the putative antidepressants buspirone and flesinoxan was found. In antagonism studies alprazolam could be antagonized (almost) completely by flumazenil, partially by pentylenetetrazole, but not by methyl 6,7-dimethoxy-4-ethylbeta;-carboline-3-carboxylate (DMCM), N-methyl-beta;-carboline-3-carboxamide (FG-7142) and picrotoxin. Conclusions: These results show that the discriminative stimulus properties of alprazolam are mediated by benzodiaze pine receptors and that the finding that antidepressants share discriminative stimulus effects with... [ABSTRACT FROM AUTHOR]

Abstract Previous drug discrimination studies with the serotonergic drug m-chlorophenylpiperazine (mCPP) showed conflicting results, with some authors concluding that the cue was mediated by 5-HT[sub 2C] receptors, but others that it was definitively not. We further examined the discriminative stimulus properties of mCPP in rats and reviewed previously published data. We trained rats to discriminate mCPP (2.0 mg/kg, PO) from water. We found that the mCPP cue generalized to m-trifluoromethyl-phenylpiperazine (TFMPP) and 6-chloro-2-(1-piperazinyl)-pyrazine (MK-212), and partially to eltoprazine, 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), fenfluramine and trazodone. A moderate level of generalization was obtained with quipazine, 1-(m-chlorophenyl)biguanide and clonidine. No generalization was found with flesinoxan, methiothepin, idazoxan and haloperidol. Mianserin and methysergide antagonized the mCPP stimulus, whereas ketanserin antagonized it partially. Metergoline, methiothepin and clozapine only marginally antagonized the mCPP stimulus. These results show that the discriminative stimulus effects of mCPP are predominantly mediated by 5-HT[sub 2C] receptors, and to some extent by 5-HT[sub 1B] receptors. When considering our results and other research together, the substitution tests clearly point to a 5-HT[sub 2C] receptor mediated stimulus, with an additional role for 5-HT[sub 1B] receptors. Antagonism studies are less clearcut, but are also suggestive of a 5-HT[sub 2C] receptor mediated effect. A definitive answer as to whether other receptors, e.g. 5-HT[sub 2B] and 5-HT[sub 7], are of any importance in mCPP's discriminative stimulus properties has to wait for more selective ligands. [ABSTRACT FROM AUTHOR]

Abstract: Recent years have seen the development of powerful technologies that have provided forensic scientists with new analytical capabilities, unimaginable only a few years ago. With liquid chromatography–mass spectrometry (LC–MS) in particular, there has been an explosion in the range of new products available for solving many analytical problems, especially for those applications in which non-volatile, labile and/or high molecular weight compounds are being analysed. The aim of this article is to present an overview of some of the most recent applications of LC–MS (/MS) to forensic analysis. To this end, our survey encompasses the period from 2002 to 2005 and focuses on trace analysis (including chemical warfare agents, explosives and dyes), the use of alternative specimens for monitoring drugs of abuse, systematic toxicological analysis and high-throughput analysis. It is not the intention to provide an exhaustive review of the literature but rather to provide the reader with a ‘flavour’ of the versatility and utility of the technique within the forensic sciences. [Copyright &y& Elsevier]

We have developed a rapid method that enables the simultaneous analysis of gamma-hydroxybutyrate (GHB) and its precursors, i.e. gamma-butyrolactone (GBL) and 1,4-butanediol (1,4-BD) in urine. The method comprised a simple dilution of the urine sample, followed by liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis. Chromatographic separation was achieved using an Atlantis dC18 column, eluted with a mixture of formic acid and methanol. The method was linear from 1–80 mg/L for GHB and 1,4-BD and from 1–50 mg/L for GBL. The limit of quantification was 1 mg/L for all analytes. The procedure, which has a total analysis time (including sample preparation) of less than 12 min, was fully validated and applied to the analysis of 182 authentic urine samples; the results were correlated with a previously published GC–MS procedure and revealed a low prevalence of GHB-positive samples. Since no commercial immunoassay is available for the routine screening of GHB, this simple and rapid method should prove useful to meet the current increased demand for the measurement of GHB and its precursors. [Copyright &y& Elsevier]

Therapeutic drug monitoring generally focuses on the plasma compartment only. Differentiation between the total plasma concentration and the free fraction (plasma water) has been described for a number of limited drugs. Besides the plasma compartment, blood has also a cellular fraction which has by far the largest theoretical surface and volume for drug transport. It is with anti-cancer drugs that major progress has been made in the study of partition between the largest cellular blood compartment, i.e., erythrocytes, and the plasma compartment. The aim of the present review is to detail the progress made in predicting what a drug does in the body, i.e., pharmacodynamics including toxicity and plasma and/or red blood cell concentration monitoring. Furthermore, techniques generally used in anti-cancer drug monitoring are highlighted. Data for complex Bayesian statistical approaches and population kinetics studies are beyond the scope of this review, since this is generally limited to the plasma compartment only. [ABSTRACT FROM AUTHOR]

ABSTRACT Aims To assess the dose–effect relationship between self-reported drug intake and the concentration of drugs and/or their metabolites in hair and to examine factors that may mediate this relationship. Design and setting A cohort study among young drug users (YDU) in Amsterdam, the Netherlands, which began in July 2000. At intake, YDU were asked to report their average drug intake over a 2-month period. A hair sample was taken and then analysed for cocaine, benzoylecgonine (BE), morphine, 6-monoacetylmorphine and methadone. Weighted least-squares regression analysis was used to model hair-test results as a function of reported drug use. Participants Subjects were 95 YDU (using cocaine, heroin, methadone and/or amphetamines at least 3 days/week) aged 18–30 residing in Amsterdam in 2000–2001. Findings Of the 95 YDU, one-third were women; mean age was almost 26; 30% had black hair, 33% blond hair and 37% brown hair. Cocaine use was reported by 92%, heroin by 75% and methadone by 64% of participants. All hair samples contained one or more drugs. Crude correlation coefficients between reported drug doses and drug concentrations in hair ranged between 0.45 and 0.59. The multivariate regression analysis showed that, for one or more types of drug, black-haired people, women and non-western European people had relatively high drug concentrations in hair (significant slope effects). The corresponding multivariate correlation coefficients ranged between 0.63 and 0.87. Conclusions Hair testing can be used to quantify drug use in epidemiological studies, given that factors such as hair colour and sex are taken into account. [ABSTRACT FROM AUTHOR]

Previous studies with mice lacking 5-HT1A (1AKO) and 5-HT1B (1BKO) receptors in hippocampus-dependent learning and memory paradigms, suggest that these receptors play an important role in learning and memory, although their precise role is unclear. In the present study, 1AKO and 1BKO mice were studied in operant behavioural paradigms of decision making and response inhibition, to further study the putative involvement of these receptors in prefrontal cortex-dependent learning and memory. Moreover, because 1AKO mice have been shown to exhibit an antidepressant-like phenotype and 1BKO mice to be more impulsive in ethological studies, mice were trained in a differential-reinforcement-of-low-rates (DRL) procedure. Overall, results indicate that 1AKO and 1BKO mice display subtle differences in operant paradigms of decision making and response inhibition compared to wild type (WT) mice. In addition, when responding under a DRL 36-s schedule had stabilised, 1BKO mice showed a phenotype indicative of increased impulsivity, whereas 1AKO mice did not differ from WT mice. In conclusion, 5-HT1B receptors appear to play an important role in impulsivity and a minor role in prefrontal cortex-dependent learning and memory as shown by the results obtained in serial reversal learning and extinction. In contrast, 5-HT1A receptors appear to be involved in facilitation of autoshaping, but their role in impulsivity and prefrontal cortex-dependent learning and memory appears to be limited. [Copyright &y& Elsevier]

5-HT1A receptor knockout (KO) mice have been described as more anxious in various anxiety paradigms. Because anxiety is often associated with autonomic changes like elevated body temperature and tachycardia, radiotelemetry was used to study these parameters in wild type (WT) and KO mice in stress-/anxiety-related paradigms. Basal body temperature (BT), heart rate (HR), and their diurnal rhythmicity did not differ between well-adapted WT and KO mice. In a simple stress-test, the Stress-induced Hyperthermia (SIH), injection-stress resulted in an exaggerated stress-response in KO mice. Furthermore, the 5-HT1A receptor agonist flesinoxan dose-dependently antagonized SIH and stress-induced tachycardia in WT, but not in KO, mice. In both genotypes, diazepam blocked SIH, but not stress-induced tachycardia. Finally, KO mice displayed an exaggerated stress response in HR and BT to novelty stress; this was supported by behavioral indications of enhanced anxiety. The present findings show that 5-HT1A receptor KO mice display a more “anxious-like” phenotype not only at a behavioral, but also at autonomic levels. [Copyright &y& Elsevier]

Previous studies in 5-HT1A receptor knockout (1AKO) mice on a mixed Swiss Webster×129/Sv (SW×129/Sv) and a pure 129/Sv genetic background suggest a differential γ-aminobutyric acid (GABAA)–benzodiazepine receptor complex sensitivity in both strains, independent from the anxious phenotype. To further investigate these discrepancies, various GABAA–benzodiazepine receptor ligands were tested in different behavioral paradigms in 1AKO and wild type (WT) mice on a 129/Sv background. 1AKO and WT mice responded comparably to alprazolam, flumazenil, alcohol and pentylenetetrazol as measured in the stress-induced hyperthermia paradigm. In addition, sedative–anesthetic effects of pentobarbital measured via the righting reflex were similar and a selected dose of diazepam exerted similar anxiolytic effects in both genotypes in the elevated plus maze. In conclusion, 1AKO mice on a 129/Sv background have undisturbed GABAA–benzodiazepine receptor sensitivity in contrast to those described on a mixed Swiss Webster×129/Sv background. The anxious phenotype of 1AKO mice seems to occur independent of the GABAA–benzodiazepine receptor complex functioning. [Copyright &y& Elsevier]

It remains often uncertain whether the use of illicit substances has contributed to the aetiology of psychosis. Gas chromatography–mass spectrometry can be used to detect them in hair of the head. Given a monthly growth rate between 1.0 and 1.5 cm, one can examine hair segments that originated during the pre-psychotic period. We examined the usefulness of hair analysis to detect the use of cannabinoids or amphetamines during this period. One hundred patients participated in a psychosis incidence study and 64 yielded hair. Refusal was associated with non-Dutch ethnicity, not with a clinical diagnosis of use. A monthly growth rate of 1.5 cm was assumed and 33 specimens were found to be long enough. Cannabinoids or amphetamines were detected in nine specimens. In seven they were not detected, whereas the patients had reported their use. It is likely that their hair grew at a slower rate and that the examined segments belonged to an earlier period of time, during which the substances were not used. Lack of knowledge about the individual hair growth rate is an important limitation to the usefulness of this method. [Copyright &y& Elsevier]

Two presynaptic receptors play an important role in the regulation of serotonergic neurotransmission, i.e., the 5-HT1A and 5-HT1B receptor. The present study focuses on putative adaptive changes in the 5-HT1A receptor system in mice that lack 5-HT1B receptors (5-HT1B KO). 5-HT1A receptor sensitivity was assessed in vivo in two models of presynaptic 5-HT1A receptor activity: agonist-induced hypothermia and prevention of stress-induced hyperthermia. The effects of 5-HT1A receptor activation by flesinoxan (0.1–3.0 mg/kg s.c.) were determined telemetrically on body temperature and heart rate in 5-HT1B KO and wild-type (WT) mice. Flesinoxan induced hypothermia dose-dependently without affecting heart rate and prevented stress-induced hyperthermia and tachycardia equipotently in both genotypes. Specificity of these responses was confirmed by blockade with the selective 5-HT1A receptor antagonist WAY100635 (1.0 mg/kg s.c.). The importance of continuous sampling in freely moving subjects to improve appropriate characterization of mutants is discussed. 5-HT1B KO mice showed no shift in 5-HT1A receptor sensitivity compared to WT mice. This study found no indications for adaptive changes in presynaptic 5-HT1A receptor function in 5-HT1B KO mice as measured telemetrically on body temperature and heart rate responses. [Copyright &y& Elsevier]

Abstract Rationale: Previous research found no adaptations in presynaptic 5-HT[sub 1A] receptors in mice lacking 5-HT[sub 1B] receptors (5-HT[sub 1B] KO). Stress and 5-HT[sub 1A] receptor agonists induce corticosterone release in mice via hypothalamus-pituitary-adrenal (HPA) axis activation. 5-HT[sub1] KO mice are hyperreactive to mild stressors and this might be reflected in altered postsynaptic 5-HT[sub 1A] receptor sensitivity. Objectives: Our aim was to determine whether the activity of the HPA axis was increased in 5-HT[sub 1B] KO mice in response to mild stress and pharmacological activation of 5-HT[sub 1A] receptors as an indication of putative adaptive changes in postsynaptic 5-HT[sub 1A] receptor function. Methods: The effect of mild stress [i.e., the stress-induced hyperthermia (SIH) paradigm], induced by rectal temperature measurement, was determined on temperature and corticosterone over time (0, 5, 10, 20, 30, 60, and 90 min) in 5-HT[sub 1B] KO and wildtype mice. In addition, corticosterone was measured 60 min after 5-HT[sub 1A] receptor activation by flesinoxan (0, 0.03, 0.1, 0.3, 1, and 3 mg/kg SC). Blood was collected and plasma corticosterone levels were determined by radioimmunoassay. Results: Both genotypes showed comparable time-dependent SIH responses, whereas basal temperature was higher in 5-HT[sub 1B] KO mice. The effect of SIH on temperature was mirrored by mild increases in plasma corticosterone. Activation of 5-HT[sub 1A] receptors caused a strong dose-dependent release of corticosterone in both genotypes. Neither response observed showed differences between both genotypes. Conclusions: Although 5-HT[sub 1B] KO mice are hyperreactive to mild stress, this reactivity is not reflected by stronger corticosterone responses in the SIH paradigm. The lack of shift in dose response curves for... [ABSTRACT FROM AUTHOR]

Iodine-131 labelled meta-iodobenzylguanidine ([[sup 131]I]MIBG) is used for diagnostic scintigraphy and radionuclide therapy of neural crest-derived tumours. After administration of therapeutic doses of [[sup 131]I]MIBG (3.1-7.5 GBq) to 17 patients (n=32 courses), aged 2-73 years, 56%±10%, 73%±11%, 80%±10% and 83%±10% of the dose was cumulatively excreted as total radioactivity in urine at t=24 h, 48 h, 72 h and 96 h, respectively. Except for two adult patients, who showed excretion of 14%-18% of [[sup 131]I]meta-iodohippuric acid ([[sup 131]I]MIHA), the cumulatively excreted radioactivity consisted of >85% [[sup 131]I]MIBG, with 6% of the dose excreted as free [[sup 131]I]iodide, 4% as [[sup 131]I]MIHA and 2.5% as an unknown iodine-131 labelled metabolite. Cumulative renal excretion rates of total radioactivity and of [[sup 131]I]MIBG appeared to be higher in neuroblastoma and phaeochromocytoma patients than in carcinoid patients. Based on the excretion of small amounts of [[sup 131]I]meta-iodobenzoic acid in two patients, a possible metabolic pathway for [[sup 131]I]MIBG is suggested. The degree of metabolism was not related to the extent of liver uptake of radioactivity. [ABSTRACT FROM AUTHOR]

Abstract To determine whether alterations in 5-HT[sub 1A] receptor mediated responses induced by a single injection with a selective 5-HT[sub 1A] receptor agonist is a transient effect, or whether the (de)sensitisation is more persistent, rats were pretreated with the selective and full 5-HT[sub 1A] receptor agonist, flesinoxan (3 mg/kg SC once daily) for either 1 day or 1 week. Twenty-four hour after the last pretreatment injection, rats were challenged with flesinoxan (3 mg/kg SC), and the effects on plasma corticosterone and prolactin levels, lower lip retraction and behaviour in the shock-probe burying test were determined. Several 5-HT[sub 1A] receptor mediated responses were modified differentially following the flesinoxan pretreatment. However, all changes induced by a single flesinoxan injection remained present upon repeated flesinoxan administration. The differential changes in the responses to flesinoxan cannot easily be explained by differences in pre- or postsynaptically 5-HT[sub 1A] mediated responses. The prolactin response to flesinoxan, which is thought to be mediated postsynaptically, was enhanced, whereas the corticosterone response to flesinoxan, which is also mediated postsynaptically, was attenuated. The presynaptically mediated lower lip retraction response was attenuated as well, whereas the behavioural effects of flesinoxan remained relatively unaffected following repeated flesinoxan administration. Upon prolonged flesinoxan pretreatment, the changes induced by a single flesinoxan injection remained present or increased further. Although repeated flesinoxan administration (1 day and 1 week) resulted in 20% lower plasma flesinoxan concentrations, this effect could not explain the neuroendocrine and behavioural findings. [ABSTRACT FROM AUTHOR]