Methamphetamine HCl Research Articles

Development of Methamphetamine Conjugated Vaccine through Hapten Design: In Vitro and In Vivo Characterization.

Methamphetamine (METH) substance-use disorder is an ever-growing global health issue with no effective treatment. Anti-METH vaccines are under investigation as an alternative to existing psychological interventions. This platform has made significant progress over past decades mainly in preclinical stages, and efforts to develop an anti-METH vaccine with a high antibody response are of utmost importance. A novel conjugated anti-METH vaccine was developed using METH HCl as the starting material for the design of hapten, a peptide linker consisting of five lysines and five glycines, and finally immunogenic carrier mannan, which is novel to this platform. All the chemical reaction steps were confirmed by several analytical techniques, and the immunogenicity of the developed vaccine was investigated in a mouse model. Thin-layer chromatography and gas chromatography confirmed the reaction between METH and peptide linker. UV, NMR and color tests were used to confirm the presence of the aldehyde groups in oxidized mannan (OM). The final conjugated vaccine was confirmed by UV and LC-MS. The stability of mannan, the METH hapten, and the final vaccine was evaluated by UV and LC-MS and demonstrated satisfactory stability over 3 months in various storage conditions. Animal studies supported the immunogenicity of the novel vaccine. We successfully developed and characterized a novel METH vaccine in vitro and in vivo. The present study findings are encouraging and will form the basis of further exploration to assess its effectiveness to prevent METH addiction in preclinical models.

Abstract 15092: The Yin-yang of Bmpr2 and Ces1 in the Pulmonary Endothelium Aad Its Role in Pulmonary Arterial Hypertension

Background/Hypothesis: Pulmonary Arterial Hypertension (PAH) is a life-threatening disease characterized by loss of pulmonary microvessels and vascular remodeling. Loss of function BMPR2 mutations contribute to pulmonary endothelial cell (EC) apoptosis and oxidative stress, but their reduced penetrance suggests need for additional modifiers. Carboxylesterase1 (CES1) is endoplasmic reticulum (ER) enzyme responsible for detoxification, proteostasis, and redox balance. Similar to BMPR2 mutations, we found that loss of CES1 is associated with oxidative stress and apoptosis. In this study, we explore a plausible link between BMPR2 pathway and CES1 regulation in promoting EC survival and angiogenesis. Methods: PECs & lung tissue from healthy donors and PAH patients were obtained from PHBI. To induce oxidative stress, we used H 2 O 2 (100 μM) & methamphetamine HCl (METH, 0.5-2mM). Both siRNA and pharmacological approaches were used to inhibit BMPR2, Nrf2, and CES1 expression. Caspase and Matrigel assays were used to assess PEC survival and tube formation, respectively. Results: RNAseq of BMPR2-mutant PECs showed significantly less CES1 expression, which correlated with reduced protein expression in PEC lysates and within lung vascular lesions. In healthy PECs, BMP9 stimulation led to increase in CES1 expression that was absent post BMPR2 knockdown. CES1 gene transcription was by BMPR2-dependent activation of Nrf2, a transcription factor responsible for antioxidant gene expression and mitochondrial biogenesis. Inhibition of Nrf2 activation by ML385 (5μM) abrogates BMP9 induced CES1 mRNA levels similar to BMPR2 knockdown. The connection between BMPR2 and CES1 was further strengthened by CES1 knockdown studies in PECs that demonstrated reduction in BMPR2 protein synthesis associated with ER stress and reduced autophagy. Finally, lung examination in CRISPR generated CES1 +/- mice demonstrated increased microvascular muscularization at normoxia compared to wild type mice. Conclusion: BMPR2 and CES1 are part of common signaling pathway that protects PECs against oxidative stress and mitochondrial damage through a positive feedback loop. Interventions that restore CES1 activity could rescue BMPR2 signaling and serve as novel PAH therapeutics.

Self-administration of methamphetamine aerosol by male and female baboons

The reinforcing efficacy of vaporized methamphetamine HCl (0.3 mg/kg) was determined in baboons with minimal previous drug exposure. A group of 8 adult male baboons was tested prior to a group of 7 adult female baboons. Baboons were initially trained to suck on a brass stem activating a pressure-sensitive relay (i.e., puff), to receive one M&M® candy. Five of the 8 males and 6 of the 7 females learned to activate the relay. 0.05 ml of 95% ethyl alcohol containing 0.3 mg/kg methamphetamine was vaporized and delivered to the mouth of the baboon after he/she completed 2 puffs; a single candy was given after an additional 5 puffs to ensure that baboons continued puffing after the aerosol entered their mouths. Puffing was recorded but not reinforced by candy or drug for 2 min after each aerosol delivery for males and 1 min for females. Males could earn 10 and females could earn 20 aerosol deliveries. Males made between 225 and 650 puffs each session. Females made between 200 and 400 puffs each session. When only candy and placebo aerosol were delivered the number of puffs decreased in all 6 females but increased in all 5 males. When candy was delivered without aerosol, puffing decreased in 4 of 5 males, but this manipulation was not tested in females. Methamphetamine aerosol delivery maintained lower rates of puffing behavior in females than males, but procedural differences weaken interpretation of this sex comparison. Although training non-human primates to inhale drug vapors is time consuming, if successful, their long lifespan could provide years of valuable data justifying further work with non-human primates using models of vaporized drug self-administration.

Isotope fractionation during precipitation of methamphetamine HCl and discrimination of seized forensic samples

Methamphetamine is a widely abused illicit drug. Increasingly, studies have focused on stable isotope analysis by isotope ratio mass spectrometry (IRMS) to link samples of methamphetamine synthesized together or from the same source of precursor. For this reason, it is important to understand potential sources of isotope fractionation that could cause variability in forensic data sets. In this study, methamphetamine free base samples were synthesized from (−)-ephedrine HCl using the HI/red phosphorus synthetic route and then precipitated as HCl salts by bubbling with HCl gas. The entire sample did not precipitate when first bubbled with gas, and multiple precipitation steps were required. Fractions of precipitate were individually analyzed for δ 13C, δ 15N and δ 2H by IRMS. Both δ 15N and δ 2H were found to become more negative, with the heavy isotopes depleted, in successive fractions of precipitate. Homogenizing the precipitate fractions together could eliminate this fractionation. However, in a clandestine situation this fractionation could lead to greater than expected δ 15N and δ 2H variability between illicit samples of methamphetamine HCl that have been synthesized from the same sample of ephedrine. This needs to be taken into account when interpreting forensic IRMS data. We also present an analysis of four separate seized case lots of methamphetamine HCl, taking into account the possible sources of fractionation and available intelligence information.

Significant Determinants of Isotope Composition During HI/Pred Synthesis of Methamphetamine

Methamphetamine HCl was synthesized using three variations of the hydriodic acid/red phosphorus (HI/Pred) synthetic route. A Plackett-Burman experimental design was used to determine how reaction parameters affected the isotopic composition of the product. Isotope ratio mass spectrometry results showed only the source of precursor 13C was significant in determining product δ 13C; the manufacturer, reaction temperature, time, scale, and source of HI were not significant. The precursor was also the main determinant of product δ 2H, with smaller contributions from the HI source for one method. From precursor to product, large δ 2H depletion occurred for most samples. Deuterium nuclear magnetic resonance spectroscopy (2H NMR) was used to investigate the specific site of this. Significant fraction of deuterium was observed only at the benzylic position, the site of hydrogen addition during synthesis. Methamphetamine synthesized from ephedrine was shown to be depleted in this position.

A processing method enabling the use of peak height for accurate and precise proton NMR quantitation

In NMR, peak area quantitation is the most common method used because the area under a peak or peak group is proportional to the number of nuclei at those frequencies. Peak height quantitation has not enjoyed as much utility because of poor precision and linearity as a result of inconsistent shapes and peak widths (measured at half height). By using a post-acquisition processing method employing a Gaussian or line-broadening (exponential decay) apodization (i.e. weighting function) to normalize the shape and width of the internal standard (ISTD) peak, the heights of an analyte calibration spectrum can be compared to the analyte peaks in a sample spectrum resulting in accurate and precise quantitative results. Peak height results compared favorably with 'clean' peak area results for several hundred illicit samples of methamphetamine HCl, cocaine HCl, and heroin HCl, of varying composition and purity. Using peak height and peak area results together can enhance the confidence in the reported purity value; a major advantage in high throughput, automated quantitative analyses.

Trace Evidence of trans-Phenylpropene as a Marker of Smoked Methamphetamine

This case study investigates trans-phenylpropene as a potential marker for smoked methamphetamine. The decedent, a 31-year-old male, was found with paraphernalia that indicated that he may have been smoking abused drugs prior to death. Methamphetamine and cocaine were detected in the residue remaining in the paraphernalia. Markers of thermal degradation of methamphetamine and cocaine were also detected in the paraphernalia. Gas chromatography-mass spectrometry (GC-MS) analysis detected trans-phenylpropene as a marker of smoked methamphetamine and anhydroecgonine methyl ester as a marker of smoked cocaine. Both trans-phenylpropene and anydroecgonine methyl ester were detected in the urine of the decedent, connecting the link between the paraphernalia for smoking and the ingestion of the pyrolysis products of methamphetamine and cocaine. Several other drugs of abuse were identified either in blood and urine or in hexane extracts of the paraphernalia, including phenylacetone, fentanyl, norfentanyl, amphetamine, ecgonine methyl ester, oxycodone, acetaminophen, chlorpheniramine, and caffeine. Using a pyrolysis GC-MS, the characteristic pyrolytic products of cocaine HCl, methamphetamine HCl, and combinations of the two were evaluated and the results showed that combining the drugs in a single run did not alter the pyrolysis pattern. The detection of trans-phenylpropene in both biological specimens and in paraphernalia is the first example of this analyte being applied as evidence of smoked methamphetamine.

Proton Nuclear Magnetic Resonance Spectroscopy (NMR) Methods for Determining the Purity of Reference Drug Standards and Illicit Forensic Drug Seizures

A rapid, sensitive, accurate, precise, reproducible, and versatile method for determining the purity of reference drug standards and the routine analysis of illicit drugs and adulterants using proton (1H) Nuclear Magnetic Resonance (NMR) Spectroscopy is presented. The methodology uses a weighed sample dissolved in a deuterated solvent or solvent mixture containing a high purity internal standard. The NMR experiment employs 8 scans using a 45 second delay and 90 degrees pulse. In the determination of purity of reference standards, the number of quantitative determinations available is equal to the number of peak groups that are baseline resolved. The relative standard deviation (RSD) of these signals is usually < 1% for pure standards, and the results agree well with other purity determining methods. This method can also aid in the determination of correct molecular weight for standards containing an unknown number of waters of hydration or an unknown number of acids per drug in salts. Because the molar response for the hydrogen nucleus is 1 for all compounds, and since no separation media are used, only one linearity study is required to test a probe. In the presented study, the linearity of the NMR probe was determined using methamphetamine HCl dissolved in deuterium oxide (D2O) with maleic acid as the internal standard (5 mg) for a range of concentrations from 0.033 to 69.18 mg/ml with a resulting correlation coefficient of >0.9999 for all 6 methamphetamine peak groups. The spectra of complex illicit heroin, methamphetamine, MDMA, and cocaine samples are presented, as well as an extensive list of compounds, their solubilities and the solvent(s) and internal standard used.

Potential Marker for Smoked Methamphetamine Hydrochloride Based on a Gas Chromatography-Mass Spectrometry Quantification Method for trans-Phenylpropene

Residue from smoked methamphetamine hydrochloride contains pyrolytic products that are detectable by gas chromatography-mass spectrometry (GC-MS). A validated GC-MS method was developed for the determination of trans-phenylpropene, a pyrolytic product of methamphetamine HCl, in residue of smoked drug as well as in human urine. trans-Phenylpropene and an isomeric internal standard, 2-phenylpropene, were extracted from urine using n-hexane. The method was validated for linearity over a range of 0.1-10 microg/mL with a limit of detection of 0.05 microg/mL, limit of quantification of 0.1 microg/mL, interday accuracy within 10.5%, intraday accuracy better than 3.7%, interday precision of 15.4%, intraday precision of 14.4%, and recovery of 89.1%. The method was applied to the detection of trans-phenylpropene found in the residue of methamphetamine HCl heated beyond its melting temperature on aluminum foil under simulated smoking conditions. The method is applicable to the detection of trans-phenylpropene in urine as a potential marker for smoked methamphetamine HCl abuse.

Long-term methamphetamine-induced decreases of [(11)C]WIN 35,428 binding in striatum are reduced by GDNF: PET studies in the vervet monkey.

The effects of glial cell line-derived neurotrophic factor (GDNF) pretreatment on methamphetamine (METH)-induced striatal dopamine system deficits in the vervet monkey were characterized with [(11)C]WIN 35,428 (WIN)-positron emission tomography (PET). WIN, a cocaine analog that binds to the dopamine transporter (DAT), was used to provide an index of striatal dopamine terminal integrity. In two subjects, GDNF (200 microg/40 microl) was injected into the caudate and putamen unilaterally vs. saline contralaterally. After 1-2 weeks, + and -GDNF striatal WIN-PET binding values were equivalent as calculated by multiple time graphic analysis, suggestive of an absence of unilateral DAT up-regulation. Three other subjects (n = 3) received GDNF injections into the caudate and putamen unilaterally and one week later, were administered METH HCl (2 x 2 mg/kg; i.m., 24 hours apart; a neurotoxic dosage for this species). At 1 week post-METH, WIN-PET studies showed that mean WIN binding was decreased by 72% in the +GDNF and by 92% in the -GDNF striatum relative to pre-drug assessment values. Thus, GDNF pretreatment reduced the extent of METH-induced decreases in WIN binding. Subsequent WIN-PET studies (1.5-9-month range) showed a protracted recovery of WIN binding in each striatum, indicative of long-term but partially reversible METH neurotoxicity. Further, at each time point, WIN binding remained relatively higher in the +GDNF vs. -GDNF striatum. These results provide further evidence that the adult non-human primate brain remains responsive to exogenously administered GDNF and that this pharmacotherapy approach can counteract aspects of neurotoxic actions associated with methamphetamine.

Long-term methamphetamine-induced decreases of [11C]WIN 35,428 binding in striatum are reduced by GDNF: PET studies in the vervet monkey

The effects of glial cell line-derived neurotrophic factor (GDNF) pretreatment on methamphetamine (METH)-induced striatal dopamine system deficits in the vervet monkey were characterized with [11C]WIN 35,428 (WIN)-positron emission tomography (PET). WIN, a cocaine analog that binds to the dopamine transporter (DAT), was used to provide an index of striatal dopamine terminal integrity. In two subjects, GDNF (200 μg/40 μl) was injected into the caudate and putamen unilaterally vs. saline contralaterally. After 1–2 weeks, + and –GDNF striatal WIN-PET binding values were equivalent as calculated by multiple time graphic analysis, suggestive of an absence of unilateral DAT up-regulation. Three other subjects (n = 3) received GDNF injections into the caudate and putamen unilaterally and one week later, were administered METH HCl (2 × 2 mg/kg; i.m., 24 hours apart; a neurotoxic dosage for this species). At 1 week post-METH, WIN-PET studies showed that mean WIN binding was decreased by 72% in the +GDNF and by 92% in the –GDNF striatum relative to pre-drug assessment values. Thus, GDNF pretreatment reduced the extent of METH-induced decreases in WIN binding. Subsequent WIN-PET studies (1.5–9-month range) showed a protracted recovery of WIN binding in each striatum, indicative of long-term but partially reversible METH neurotoxicity. Further, at each time point, WIN binding remained relatively higher in the +GDNF vs. –GDNF striatum. These results provide further evidence that the adult non-human primate brain remains responsive to exogenously administered GDNF and that this pharmacotherapy approach can counteract aspects of neurotoxic actions associated with methamphetamine. Synapse 35:243–249, 2000. © 2000 Wiley-Liss, Inc.

Trace Elemental Analysis of Illicit Methamphetamines Using Total Reflection X-Ray Fluorescence Spectroscopy

Total reflection X-ray fluorescence spectroscopy (TXRF) was applied to trace elemental analysis of 50 kinds of seized methamphetamines, a half of which had been classified to be pure and the remainder to be impure. As trace elements, Br, Hg, I, Ca, Fe, Cr, Mn, Ni, Cu and Zn were detected. Among them, Br was detected in all samples and its content was distributed between 0.4ng and 71ng per 1mg of methamphetamine HCl and Hg was detected in 8 samples and its content was distributed between 0.8ng and 9ng per 1mg of methamphetamine HCl. Iodine was detected in 8 samples, among which 6 samples also contained Hg. Hg and I were presumed to be derived from synthetic reagents. Iron and other heavy metals would be derived from impurities in synthetic solvents or metal containers through synthetic or smuggling processes. Elements detected in seized methamphetamines are applicable as tracing markers for the ascertainment of clandestine synthetic techniques or places to make illicit methamphetamine salts.

Pharmacological effects of methamphetamine and other stimulants via inhalation exposure

The effects of methamphetamine–HCl, methcathinone–HCl, cocaine and ephedrine on locomotor stimulation were compared between inhalation exposure and i.v. injection in mice. Methamphetamine–HCl was readily volatilized upon heating at 300°C in a glass pipe with only trace amounts of amphetamine being produced. The ED50 dose (9.4 and 6.5 μmol/kg for inhalation exposure and i.v. injections, respectively) and biodisposition of methamphetamine–HCl were similar for both routes of administration. Methcathinone–HCl and cocaine were readily volatilized. Their dose response profiles also appeared similar for both routes of administration. Ephedrine did not appear to be easily volatilized and was only effective in stimulating locomotor activity after i.v. administration. These findings indicate that inhalation exposure to methamphetamine–HCl, cocaine and methcathinone possess similar pharmacological characteristics as the i.v. route of administration. In particular, this model may have implications in predicting the pharmacological activity of various stimulants via the inhalation route of administration.

Characteristics of Behavioural Stimulant Effect of N‐Cyanomethylmethamphetamine, a Main Product of Smoking Methamphetamine Mixed with Tobacco: Evaluation by Ambulatory Activity in Mice

N-cyanomethylmethamphetamine is main product of smoking methamphetamine HCl (CAS code value: 537-46-2, molar mass: 185.70 g/mol) mixed with tobacco, and has a central stimulant action. The aims of this study were to assess in terms of ambulation in mice whether repeated administration of N-cyanomethylmethamphetamine HCl (molar mass: 211.70 g/mol) induced sensitization to its central stimulant effect, and whether there were cross-sensitization from N-cyanomethylmethamphetamine HCl to methamphetamine HCl, and from methamphetamine HCl to N-cyanomethylmethamphetamine HCl. N-cyanomethylmethamphetamine HCl 14.2 and 47.2 mumol/kg subcutaneously dose-dependently accelerated ambulation of mice. Five administrations at 3 day intervals caused sensitization, the activity counts in the fifth administration being approximately 2.6 and 1.6 times, higher respectively, than those in the first administration. Furthermore, the mice repeatedly given 14.2 and 47.2 mumol/kg N-cyanomethylmethamphetamine HCl exhibited cross-sensitization to methamphetamine HCl (10.8 mumol/kg subcutaneously). Whereas 1.4 and 4.7 mumol/kg N-cyanomethylmethamphetamine HCl did not induce significant acceleration of the ambulation throughout the 5 repeated administrations, nor cross-sensitization to methamphetamine HCl. On the other hand, the 5 repeated administrations of methamphetamine HCl (10.8 mumol/kg) also caused sensitization to its ambulation-increasing effect, and the activity count in the fifth administration attained approximately 2.0 times higher than that in the first administration. The mice given methamphetamine HCl demonstrated cross-sensitization to 1.42-14.2 mumol/kg N-cyanomethylmethamphetamine HCl. Haloperidol (CAS code value: 52-86-8, molar mass: 375.88 g/mol; 0.027-0.80 mumol/kg subcutaneously) dose-dependently reduced the ambulation-increasing effects of N-cyanomethylmethamphetamine HCl and methamphetamine HCl in the drug-naive, and N-cyanomethylmethamphetamine HCl- and methamphetamine HCl-sensitized mice. These dose-effect relationships were similar between groups. The present results suggest that N-cyanomethylmethamphetamine HCl has a behavioural stimulant effect almost similar to that of methamphetamine HCl.

Methamphetamine Toxicity Prevented by Activated Charcoal in a Mouse Model

Study objective: To determine the effectiveness of activated charcoal in preventing toxicity from oral methamphetamine HCl. Design: Randomized, prospective, nonblinded, controlled animal study. Setting: Animal care facility. Participants: CD-1 male mice. Interventions: Mice were given 100 mg/kg methamphetamine HCl (lethal dose 60) in water by oral gavage. Within 1 minute of methamphetamine administration, mice received either 1 g/kg activated charcoal or an equivalent volume of water as control. Measurements and main results: Mice were observed for time to onset of symptoms (piloerection, agitation, and tremor) and mortality at 1, 24, and 48 hours. Activated charcoal delayed onset of symptoms (5.53±1.25 minutes versus 4.27±1.22 minutes, P<.002) and decreased mortality compared to controls at 1 hour (1 of 20 versus 10 of 20, P<.003) and 24 hours (five of 20 versus 12 of 20, P<.05). There was no difference between groups in mortality at 48 hours. Conclusion: A single dose of activated charcoal given after oral methamphetamine delayed onset of toxicity and decreased early mortality in mice. There was no effect on overall mortality. [McKinney PE, Tomaszewski C, Phillips S, Brent J, Kulig K: Methamphetamine toxicity prevented by activated charcoal in a mouse model. Ann Emerg Med August 1994;24:220-223.]

Preliminary evidence for methamphetamine-induced behavioral and ocular effects in rat offspring following exposure during early organogenesis.

Gravid Sprague-Dawley CD (VAF) rats received 50 mg/kg (d,l)-methamphetamine (MA) HCl (expressed as free base, N = 15) or distilled water (N = 6) by SC injection x 2/day in a 3 ml/kg volume on embryonic (E) days 7-12. Control rats were pair-fed to MA-exposed dams on days E7-18. No control dams failed to deliver; however, of 15 MA-exposed dams 4 did not deliver (2 died and 2 had completely resorbed litters). One additional MA litter had all the offspring die shortly after birth. There was no difference between groups on offspring postnatal (P) body weight. The offspring exposed prenatally to MA had significantly lower olfactory orientation scores (P9, 11, 13) to their home cage scent. In a test of early activity (P10, 12, 14) the MA-exposed progeny were marginally less active than controls. MA-exposed offspring exhibited hyperreactivity and marginally shortened response latency on a test of acoustic startle (P27). Motor activity showed no differential response in MA treated or control offspring to MA (P63) or fluoxetine challenge (P70). However, the MA offspring were more active than controls with respect to central and side activity during the second week of testing. No group differences were found for performance in a straight swimming channel or on the number of errors committed or latency to escape in a complex (Cincinnati) water maze (P84). Prenatal exposure to MA also induced eye defects (i.e., anophthalmia, microphthalmia and folded retina) in 16.7% of the progeny. However, MA did not effect hippocampal or neostriatal monoamine levels when measured on P28.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of Methamphetamine HCl and Ephedrine HCl Contents by Mean of Multi-variate Analysis of X-ray Diffraction Data.

Ten samples of powder mixtures containing known quantities of methamphetamine·HCL and ephedrine·HCl were measured by X-ray diffraction. The respective I/IO values of 19 peales were selected for calibration. The data was used for the multivariate analyses including a cluster analysis, and a cluster analysis derived from the deviation and a principal component analysis. Subsequently the approximate values of the methamphetamine·HCl contents of unknown samples were determined from the 12×19 matrix. The accurate methamphetamine·HCl contents of unknown samples were calculated from the principal component score. Differences between the theoretical and calculated values of 10 samples ranged from -1.4 to 1.7% (the respective methamphetamine·HCl contents are 3.9, 14.5, 20.2, 34.4, 44.0, 49.8, 60.0, 75.2, 96.1 and 99.1%).

Clinical Effects of Daily Methamphetamine Administration

This study investigated alterations in the disposition and pharmacodynamics of methamphetamine HCl after daily administration. Six male paid volunteers familiar with the use of amphetamines participated. Each subject was administered 10 mg of methamphetamine HCl as a slow-release preparation (Desoxyn Gradumets) at 9 a.m. for 13 consecutive days (days 2-14 of the study). On days 1 and 15 the subjects were challenged with 10 mg of oral deuterated methamphetamine HCl. Deuterated drug was used to differentiate plasma concentrations of challenge doses from those of daily doses. The heart rate, subjective perception of "high," and plasma concentrations of methamphetamine were examined on days 1 and 15. Repeated ANOVA measures indicate that a significant decrease in heart-rate acceleration in response to methamphetamine challenge occurred on day 15 [F(1,5) = 8.26, p less than or equal to 0.035]. However, no significant change in either the subjective ratings of "high" or the plasma concentrations of deuterated methamphetamine occurred. These findings indicate that the disposition of methamphetamine and its subjective effects were not altered by this period of daily exposure to a low dose of the drug. In contrast, tolerance to the heart-rate accelerating effect was observed.

Saccharin preferences in food deprived aging rats are altered as a function of perinatal drug exposure

The purpose of this long-term experiment was to determine if perinatal exposure to CNS activating drugs resulted in early and/or altered onset of aging, as measured by changes in preference for preferred concentrations of saccharin solutions. Seventy-nine primiparous Sprague-Dawley rats received twice daily subcutaneous injections of either 3.0 mg/kg or pure nicotine, 5.0 mg/kg of methamphetamine HCL, 5.0 mg/kg of saline vehicle, or no injections during the 21 day gestational period and during days 3–21 of the nursing period. Twelve male offspring were randomly selected from each treatment condition, and at six months of age, they were presented with a choice of 0.20, 0.10, 0.05, 0.025, 0.01, and 0.005% of saccharin in a tap water solution and plain tap water at three month intervals. Each concentration was paired with water and presented for a 48 hr period. Eight sessions were analyzed, which spanned the ages of 15 36 months. Multivariate analyses revealed that: (1) The preference for individual saccharin concentrations across time differed as a result of maternal treatment. Differences were primarily due to the drug treatments and not to injection, (2) The pattern of saccharin preference changed over time as a function of maternal treatment but the overall level of saccharin consumption was not affected. These shifts were due to the drug treatments, not injection per se, (3) The total amount of saccharin solution consumed over time did not differ significantly among treatments, (4) The total amount of fluid consumed over the mature lifespan (saccharin solution plus water) decreased for all rats irrespective of maternal treatment. Other differences over time in total fluid consumption paralleled the saccharin index measures described above. Thus, perinatal treatment had a lasting effect upon preference for nonnutritive sweet solutions. The significance of this for aging organisms is discussed.

Circadian variation in methamphetamine- and apomorphine-induced increase in ambulatory activity in mice.

The existence of circadian variation in methamphetamine- and apomorphine-induced change in ambulatory activity in mice was investigated. Adult male mice of dd strain, which had been housed on a 12 hr light-dark schedule (light period; 6:00-18:00) for 4 weeks, received injections of either methamphetamine HCl 1 or 2 mg/kg SC at one of six times of day (3:00, 7:00, 11:00, 15:00, 19:00 and 23:00), or apomorphine HCl 0.5 or 1 mg/kg SC at one of six times of day (3:30, 7:30, 11:30, 15:30, 19:30 and 23:30). The control animals were administered a physiological saline vehicle alone at the corresponding times of day. The ambulatory activity of each mouse was measured by a tilting-type activity cage for 3 hr after methamphetamine, and for 1 hr after apomorphine. A circadian variation in the ambulatory activity was observed after the administration of the saline, methamphetamine and apomorphine. Here, the highest activity counts were found when the saline, methamphetamine and apomorphine were administered during the late dark period (3:00 or 3:30), while the lowest activity counts were found when the saline and apomorphine 1 mg/kg were administered during the mid light period (11:00 or 11:30), and methamphetamine 1 and 2 mg/kg and apomorphine 1 mg/kg were administered during the late light period (15:00 or 15:30). The circadian variation in methamphetamine-induced increase in the activity was abolished by a pretreatment with reserpine 2 mg/kg SC 4 hr before, but that of apomorphine was maintained even by the pretreatment with reserpine. The present results suggest that the methamphetamine- and apomorphine-induced increase in the ambulatory activity in mice is dependent on the time-of-day of the drug administration, and the occurrence is mainly due to a circadian variation in activity of the catecholaminergic systems in the brain.