NIDA research monograph

Online ISSN: 1046-9516
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Article
This study represents the largest clinical trial reported to date that demonstrated the efficacy of buprenorphine for opioid dependence treatment (Johnson et al. 1992). Although the study design was adequate to demonstrate differences between treatment groups, there has not been a consensus regarding the most appropriate method for analyzing various outcome measures of this and similar studies. To present a comprehensive review of these methods, other chapters in this monograph focus on various analytical techniques for assessing one of these measures--urine toxicology screens--for illicit opioids.
 
Formalin-induced biphasic nociceptive response in male Swiss Webster mice 
Analgesic dose-response curves of morphine in the early (panel a) and late (panel b) phases of the formalin test 
Development of tolerance to the analgesic effects of ACEA-1011 (panel a) and morphine (panel b) in the formalin test. In panel a, *, **, and *** indicate a significant difference from DMSO-and ACEA-1011-treated groups at p < 0.05 andp < 0.02, respectively. In panel b, *, **, and *** indicate a significant difference from saline-treated group atp < 0.05, p < 0.02, and p < 0.01, respectively. 
Article
Formalin-induced tonic nociception, which may resemble human postoperative pain, is used widely as a method for evaluating the antinociceptive effect of a mild analgesic (Hunskaar and Hole 1987; Hunskaar et al. 1985). Microinjections of diluted formalin into one of the hind paws in mice produce a biphasic nociceptive response (Rosland et al. 1990; Shibata et al. 1989; Vaccarino et al. 1993) consisting of a transient early phase followed by a tonic late phase, suggesting different pain pathways (Dubuisson and Dennis 1977; Hunskaar and Hole 1987; Hunskaar et al. 1985; Shibata et al. 1989). For example, it is known that morphine and other centrally acting analgesics produce antinociception in both phases of the formalin test, whereas most of the steroidal and nonsteroidal anti-inflammatory drugs are active only in the late phase of the test (Hunskaar and Hole 1987; Hunskaar et al. 1985; Shibata et al. 1989). Tolerance to the analgesic effect of morphine has been demonstrated following acute and chronic administration of the drug (Huidoboro et al, 1976; Kometsky and Bain 1968; Lutfy and Yobum 1991; Way et al. 1969). There are few articles (Abbot et al. 1981, 1982), however, discussing the development of tolerance in the formalin test, which has more clinical relevance than the acute procedures such as tail flick or hot plate tests.
 
Article
A method for quantitative measurement of delta 9-THC concentrations in plasma has been developed and applied to the analysis of more than 2000 samples over the past 4 years. The method includes addition of deuterium-labeled delta 9-THC to the plasma for use as the internal standard, a simple and relatively rapid solvent extraction procedure, formation of the trimethylsilyl derivative, and quantitation by selected ion monitoring using ammonia chemical ionization. A similar procedure has also been developed for simultaneous analysis of delta 9-THC and two of its major metabolites in plasma. The latter procedure requires use of a glass capillary column for assays of plasma samples in which the delta 9-THC concentration is below 10 ng/ml. Sensitivities for both methods permit quantitation of THC and its metabolites at concentrations as low as 0.2 ng in 1-ml plasma samples.
 
Article
Iodination of the kappa-selective peptide DPDYN, [D-Pro10]-dynorphin (1-11), has been performed. The non radioactive monoiodo derivative of DPDYN retains kappa-selectivity (kappa/mu = 48 and kappa/delta = 140), despite a general but moderate decrease in affinity. Radioiodination of DPDYN leads to the monoiodinated peptide (S.A 700-800 Ci/mmol) which interacts specifically and reversibly with the kappa-sites in guinea-pig cerebellum membranes with high affinity (KD = 0.12-0.18 nM). In guinea-pig brain (mu-delta-kappa) and rabbit cerebellum (kappa much less than mu), 125I-DPDYN discriminates between kappa- and other (mu, delta) binding sites. We have used this new labelled probe for the direct, precise and rapid (exposure time less than 100 hours) visualization of kappa-sites in guinea-pig and rabbit cerebellar slices using autoradiography.
 
Article
Simultaneous native molecule and discrete metabolite immune assays were performed after exposure of subjects to standardized Δ9-THC cigarettes. Plasma (and urine) 11-nor-9-carboxy-Δ9-THC remains elevated long after Δ9-THC becomes scant or undetectable enabling simple radioimmune determination of recent versus distant exposure to multiple cigarettes.
 
Article
A membrane-bound enkephalin (ENK) -hydrolyzing amino-peptidase (AP) was partially purified from neuroblastoma (clone N1E-115) cell membranes; enzyme activity was assayed by determination of the leu-enkephalin (LENK) degradation product, tyrosine (Tyr), with HPLC. The enzyme was extracted with Triton X-100, resolved by anion-exchange chromatography and further purified by gel filtration. The overall purification was about 100-fold with a yield of 43%. The apparent Mr value of the AP by gel filtration in the presence of 0.3% Triton X-100 was approx. 400 kDa. In the absence of detergent the apparent Mr value was about 305 kDa. In the elution buffers, where Triton X-100 was omitted, the peptidase activity was lost. The enzyme had a Km of 0.13 mM and a Vmax of 450 nmoles per mg protein per min at 25 degrees C for LENK and exhibited little sensitivity to bestatin (IC50: 200 microM) and puromycin (IC50: 500 microM), but it was strongly inhibited by amastatin (IC50: 8 microM). The enzyme is an amphiphilic membrane protein; the native primary structure is preserved only in the 'detergent form'. It seems to be AP N (EC 3.4.11.2) with an optimum of pH 7.2 to 7.4. We assume that this AP plays the important role in inactivating ENKs on the neuronal level. The ENK-degrading AP, partially purified from primary rat brain astrocyte cell membranes, exhibited a smaller apparent Mr value (130 kDa) and a higher sensitivity to amastatin (IC50: 0.4 microM), bestatin (IC50: 90 nM) and puromycin (IC50: 5 microM) than did the N1E-115 enzyme.(ABSTRACT TRUNCATED AT 250 WORDS)
 
Article
A radioimmunoassay for delta-9-THC in plasma, whole blood, or hemolyzed blood specimens has been presented. Samples and standards were diluted with methanol and centrifuged. An aliquot of the supernatant fluid was incubated with RIA buffer, 125I-labeled delta-8-THC and rabbit anti-THC serum. Solid phase goat anti-rabbit immunoglobulins were added to separate bound from free THC. After centrifugation the supernatant fluid was aspirated and the radioactivity of the precipitate was counted in a gamma counter. The concentration of THC was calculated from a standard curve using the logit-log transformation of the average counts of duplicate tubes. The assay had several advantages. Methanol dilution gave better results than direct analysis. The 125I-labeled THC had high specific activity and could be counted in a gamma counter. The immunological separation of antibody-bound THC from free THC was better than separation techniques using ammonium sulfate and activated charcoal. THC was determined in 0.1 ml of sample with a sensitivity of 1.5 ng/ml in plasma and 3.0 ng/ml in hemolyzed blood.
 
Article
Affinity crosslinking of human 125I-beta-Endorphin to cell lines possessing either mu or delta binding sites was carried out. Autoradiography of SDS-PAGE gels from these crosslinked cell lines revealed that these two sites contain major peptide subunits that differ in molecular size. This confirms our earlier finding in mammalian brain which demonstrated separate and distinct subunits for mu and delta opioid receptors.
 
Article
Dynorphin A (Dyn A)-related peptides have been implicated in the pathophysiology of spinal cord injury in part because their intrathecal (i.t.) injection causes hindlimb paralysis. The effects of paralytic doses of i.t. Dyn A (1-13) and Dyn A (3-13) on spinal cord blood flow and cardiac output were examined in rats using radiolabeled microspheres. Both Dyn A (1-13) and Dyn A (3-13) significantly reduced blood flow in lumbosacral spinal cord without altering cardiac output. Pretreatment with naloxone failed to block these reductions in blood flow. Thus, the paralytic effects of Dyn A may result from non-opioid actions of Dyn A to reduce spinal cord perfusion.
 
Article
The 13C-NMR spectra reported in these studies give direct evidence for the presence of two contributing conformers for alpha-methadol hydrochloride, alpha-acetylmethadol hydrochloride and beta-acetylmethadol hydrochloride. Indirect evidence is also available for the presence of more than one conformer for beta-methadol hydrochloride. However, in order to be more descriptive about the structures of the conformers, it is necessary to obtain 13C-NMR spectra that have a higher degree of resolution than is available from our present NMR system. Such systems are available, and plans are currently in progress to obtain 13C-NMR spectra or these compounds at high enough magnetic fields and low enough temperatures to give us the necessary data.
 
Article
Dynorphin A (1-13) acutely elevated the seizure threshold (ST) to the convulsant flurothyl, and this action was not blocked by naloxone. Increases in ST were also observed following i.c.v. injections of the non-opioid fragment dynorphin A (3-13). Pretreatment with dynorphin A (1-13), but not dynorphin A (3-13), non-competitively blocked the anticonvulsant effect of the mu selective opioid DAGO. Furthermore, pretreatment with dynorphin A (1-13) antagonized the delta antagonist properties of naloxone or ICI 154,129 in this seizure model. Thus, in addition to its non-opioid anticonvulsant effects, dynorphin A (1-13) exhibits unique antagonist actions which appear to be specific for the active opioid fragment.
 
Article
Our examination of 136 cocaine-abusing patients who sought treatment revealed impairment in the following areas: Psychological (99 percent of patients); Interpersonal (87.5 percent); Financial (83 percent); Physical (81 percent); and Vocational (68 percent). Daily dose did, but route of administration did not, contribute to degree of impairment. From these data, we conclude that cocaine's deleterious effects are both physiological and psychological. It appeared to us that maintenance of a cocaine habit is frequently at great expense to the user, regardless of whether the use is intranasal, intravenous, or free-base smoking. In our opinion, it is the multiplicity of psycho-social factors which drives patients to treatment. These factors also define most accurately the extent of consequences associated with cocaine use.
 
Article
In the event that methamphetamine evokes HO. formation within serotonergic axon terminals, the resultant oxidation of 5-HT would be expected to generate not only 5,6-DHT but also T-4,5-D, 7-S-Glu-T-4,5-D, 6, 8, and 7,7'-D (figure 1), at least three of which (T-4,5-D, 7-S-Glu-T-4,5-D, and 6) are lethal in mouse brain. Furthermore, several intermediates/products formed in the in vitro oxidation of 5-HT by HO. are readily autoxidized (4,5-DHT, 5,6-DHT, 5, 7, and 9) or redox cycled (T-4,5-D, 6, 8, 7,7'-D, 7-S-Glu-T-4,5-D) in reactions that would be expected to yield O2-. and/or H2O2 as byproducts. These byproducts, in the presence of trace levels of transition metal ion catalysts, would be readily converted into HO. (Walling 1975; Halliwell and Gutteridge 1984). Together these putative aberrant oxidative metabolites of 5-HT and HO.-forming reactions might contribute to the degeneration of serotonergic nerve terminals. Similarly, the methamphetamine-induced intraneuronal formation of HO. in dopaminergic terminals might be expected to generate not only 6-OHDA (and 2-OHDA and 5-OHDA, figure 3) but also 5,-S-CyS-DA and 5-S-Glu-DA, precursors of DHBT 17 and other more complex dihydrobenzothiazines (figure 4). DHBTs 17 to 19 are lethal in mouse brain, although at this time the biochemical/chemical mechanisms underlying this toxicity and specific neuronal systems affected are unknown. However, 5-S-CyS-DA and 17 to 19 are much more easily oxidized than DA, and the latter DHBTs appear to be capable of redox cycling reactions (Zhang and Dryhurst 1994). Thus, the HO.-mediated oxidation of DA in dopaminergic nerve terminals induced by methamphetamine might be expected to generate aberrant oxidative metabolites that (as a result of autoxidation and redox cycling reactions) potentiate formation of O2-. and/or H2O2, and then HO. and neuronal damage. A number of lines of evidence, discussed previously, suggest that aberrant metabolite(s) of DA (other than or in addition to 6-OHDA) might contribute to the methamphetamine-induced degeneration of not only dopaminergic terminals but also serotonergic terminals. Similarly, aberrant metabolite(s) of 5-HT (other than or in addition to 5,6-DHT) might be involved in the degeneration of serotonergic and dopaminergic terminals and a subpopulation of cell bodies in the somatosensory cortex. Experimental evidence indicates that some of the neurodegenerative effects evoked by methamphetamine are mediated by NMDA and GABA receptors. Thus, it will be of considerable interest to investigate the neurotoxicity of putative aberrant oxidative metabolites of 5-HT (figures 1 and 2) and DA (figures 4 and 5) towards serotonergic, dopaminergic, and other neuronal systems and their interactions with NMDA, GABA, and other brain receptors. A central question relates to mechanisms by which methamphetamine might evoke the intraneuronal formation of oxygen radicals that appear to play important roles in the overall neurodegenerative processes evoked by this drug (DeVito and Wagner 1989; Cadet et al. 1994). Once putative oxidative metabolites of 5-HT such as T-4,5-D, 7-S-Glu-T-4,5-D, 5,6-DHT, 6, 8, and 7,7'-D (figure 1) are formed intraneuronally, autoxidation/redox cycling reactions should, in principle, be capable of generating O2-. and/or H2O2, the precursors of HO.. Similarly, intraneuronal formation of 6-OHDA, 5-S-CyS-DA, and DHBTs 17 to 19 and 22 would also be expected to potentiate elevated fluxes of O2-., H2O2, and HO. as a result of the facile autoxidation/redox cycling reactions of these putative aberrant metabolites. The presence of very low concentrations of 5-S-CyS-DA in DA-rich regions of human and other mammalian brains suggest that autoxidation (Rosengren et al. 1985; Fornstedt et al. 1986, 1989, 1990) or perhaps some other form of DA oxidation is a normal reaction in vivo. Furthermore, available evidence suggests that it is cytoplasmic DA that is oxidized to give 5-S-CyS-DA (Fornstedt et al. 1989; Fornstedt and
 
Article
BMY 14802 was identified as a potential antipsychotic drug in traditional model systems, and this identification was confirmed in modern behavioral and electrophysiological systems. The drug appears to be atypical as an antipsychotic in its lack of activity in models predictive of the potential to produce extrapyramidal side effects and tardive dyskinesia. Indeed, this suggestion is corroborated by clinical findings to date. The atypical profile of BMY 14802 extends to its neurochemical actions and appears to find its basis in regionally selective, indirect modulation of the dopamine system. Furthermore, BMY 14802 exhibits interactions with sigma binding sites in vitro and in vivo, a notion supported by data from neurophysiological, behavioral, and biochemical investigations. BMY 14802 also appears to be neuroprotective in some model systems and may have utility in the treatment of stroke (Boissard et al. 1991). BMY 14802 appears to interact with 5-HT1A receptors, but this interaction does not seem to contribute significantly to the potential antipsychotic actions of the drug. Moreover, the formation of active metabolites of BMY 14802 does not appear to occur in animals or humans to an extent of physiological or behavioral relevance. If clinically efficacious, BMY 14802 may treat the symptoms of schizophrenia by a mechanism novel for antipsychotic drugs: regionally selective, indirect modulation of dopaminergic systems by specific interaction at sigma sites.
 
Article
In 17 studies of naltrexone, a totoal of 1,536 patients had been logged in as potential study subjects as of February 29, 1976. Of these, 883 had been started on study medication, including 107 on placebo as controls. A relatively high rate of attrition was seen in all studies over the first two months of study medication; this attrition rate tended to flatten out at about the fourth month. Of the 883 subjects beginning study medication, 47 (5.3%) were subsequently terminated for medical reasons. The data available on 45 of these subjects indicate equivalent percentages, both with respect to the total number of dropouts in the two study medication groups (naltrexone: 39 of 676, or 5.0%; placebo: 6 of 107, or 5.6%) and to the number of dropouts which the clinic reported as "possibly drug-related" (naltrexone: 6 out of 676, or 0.9%; placebo: 1 of 107, or 0.9%). However, one of the "possibly drug-related" dropouts developed idiopathic thrombocytopenic purpura after the administration of naltrexone for approximately 13 months during four separate treatment admissions. Statistical review of the data and subsequent analyses of the five double-blind, placebo-controlled studies administered by the National Academy of Sciences revealed no significant medication-group differences with respect to the physical/psychiatric or laboratory data. A review of the symptom data and analyses indicates that the frequency of occurrences of certain of the gastrointestinal tract symptoms recorded was somewhat higher in those subjects treated with naltrexone. Specific symptoms involved included "Loss of Appetite", "Abdominal Pain or Cramps", "Nausea or Vomiting", and "Constipation". However, the relative severity of these symptoms for all subjects experiencing any symptomatology was not statistically differentiable with respect to study medication group.
 
Article
D-ala2-met5-enkephalinamide (DAME) produced a dose-related increase in the mean arterial blood pressure of conscious, unrestrained rats. Intravenous injection of DAME (0.5, 1, 2, and 4 mg/kg) resulted in mean systemic arterial blood pressures of 138 +/- 2, 146 +/- 5, 141 +/- 4, 156 +/- 5 mmHg, respectively. 17-alpha-estradiol and its derivatives are known to be inactive in target tissues responsive to estrogenic hormones such as 17-beta-estradiol. However, LaBella et al. (1978) found after testing a large number of steroid hormones and their metabolites that only 17-alpha-estradiol significantly inhibited binding of 3H-naloxone, an opiate antagonist, in rat-brain homogenates. The present study was designed to determine whether 17-alpha-estradiol could antagonize the cardiovascular responses elicited by intravenous injections of DAME. Intravenous infusion of 17-alpha-estradiol (1.5 mg/kg) every 2 hours for 24 hours (total infusion time was 2 minutes for each infusion) did not change the mean systemic arterial blood pressure (94 +/- 5 mmHg) compared to the blood pressure prior to infusion of 17-alpha-estradiol (99 +/- 7 mmHg). Intravenous infusion of 17-alpha-estradiol (1.5 mg/kg) 10 minutes prior to DAME (1 mg/kg, i.v.) resulted in a blood pressure of 106 +/- 9 mmHg, which is significantly less than the blood pressure of 146 +/- 5 mmHg seen with DAME (1 mg/kg, i.v.) alone. Intravenous injection of DAME (1 mg/kg) 8 hours after the last infusion of 17-alpha-estradiol produced an increase in mean systemic arterial blood pressure of 136 +/- 8 mmHg. These results indicate that 17-alpha-estradiol may function as an opiate antagonist.
 
Article
Dynorphin A(1-17), the proposed endogenous ligand for the kappa receptor, has been reported to demonstrate no antinociceptive activity when tested in analgesic assays involving noxious (heat (e.g., tail-flick and hot-plate assays). By using a rat tail-flick analgesic assay that utilizes extreme cold as its noxious stimulus (an ethylene glycol-water mixture maintained at -10 degrees C), we have recently reported a dose-related and naloxone-reversible antinociceptive effect for i.c.v. administered dynorphin A(1-17). To elucidate the biochemical mechanism of this antinociception, we designed a push-pull perfusion system which would allow us to measure changes in neuropeptide release in the spinal cord during exposure to noxious heat or cold. Male Sprague-Dawley rats were implanted surgically with two lengths of PE-10 tubing inserted into the spinal subarachnoid space via the cisterna magna, with the push cannula at the level of T-1, and the pull cannula at the rostral edge of the lumbar enlargement. At the time of testing, samples of cerebrospinal fluid were collected both in the presence and absence of a noxious stimulus. Substance P (SP) and somatostatin (SST) levels were measured by radioimmunoassay. Exposing the animal's tail to the noxious cold (30 sec/min for 20 min) resulted in a significant elevation in SP release (69% above base-line levels), but no change in the level of SST release. Conversely, exposure to noxious heat (50 degrees C, 20 sec/min for 20 min) produced a significant increase in SST release (56% above base line), but no change in the level of SP release.(ABSTRACT TRUNCATED AT 250 WORDS)
 
Article
BAM-18, a new endogenous opioid containing 18 amino acid residues, was tested in 3 behavioral paradigms. Tail-flick analgesia, a spinally mediated response, hot-plate analgesia, a centrally mediated response, and open-field locomotor activity. Rats were stereotaxically implanted with a unilateral cannula aimed at the lateral ventricle. Following recovery, each animal was tested in one of the paradigms after receiving an intraventricular injection of BAM-18, morphine or the Ringer's vehicle. BAM-18 produced significant tail-flick analgesia only at doses (50 micrograms) 50 times higher than those needed with morphine (1 microgram). BAM-18 produced an extended hyperalgesia at lower doses (5 micrograms) that was also seen transiently at the high dose. The analgesia but not the hyperalgesia was reversed by naloxone (10 mg/kg, s.c.). BAM-18 produced significant naloxone-reversible hot-plate analgesia, but again it was less potent than morphine (50 micrograms for BAM-18 vs. 5 micrograms for morphine). There was no evidence of hyperalgesia in this paradigm. Locomotor activity, following 50 micrograms of BAM-18, resembled control injections for the first 18 minutes, then became reduced in a manner similar to morphine (5 micrograms). This reduction in activity was completely reversed by naloxone. These data suggest that BAM-18 is indeed an opioid molecule but is at least 10 times less potent at altering behavior than morphine.
 
Article
The opioid receptor selectivity of BAM 18 was determined by radioligand binding and peripheral tissue bioassay. Using selective radioligand binding conditions, BAM 18 bound to the mu opioid receptor with an affinity twice that of the K receptor and over 10 times that of the delta opioid receptor (Ki = 0.29, 0.84 and 3.9 nM, respectively). Ke values for naloxone antagonism of BAM 18 activity in the electrically stimulated guinea pig ileum and the mouse vas deferens were 4.3 and 9.9 nM respectively. The pharmacological profile of BAM 18 was similar to that of metorphamide.
 
Article
Methods for obtaining small area estimates which have emerged over the past decade are reviewed with particular emphasis given to synthetic estimation, a procedure originally developed at the National Center for Health Statistics which has found wide acceptance because of its simplicity and intuitive appeal, and yet has provoked much controversy because of its lack of good demonstrable statistical properties and its equivocal results when subjected to empirical evaluation. The various methods of obtaining small area estimates are discussed in terms of their statistical properties, the feasibility of using them and the potential scope of their application. Finally, some recommendations are made concerning possible avenues of future research in small area estimation, and some tentative guidelines are given for choosing between alternative existing methods.
 
Top-cited authors
Charles O'Brien
  • University of Pennsylvania
Anna Rose Childress
  • University of Pennsylvania
Lana Debra Harrison
  • University of Delaware
George Woody
Roy Alfred Wise
  • National Institute on Drug Abuse