Atypical binding at dopamine and serotonin transporters contribute to the discriminative stimulus effects of mephedrone

Impacts of Self-Administered 3,4-Methylenedioxypyrovalerone (MDPV) Alone, and in Combination with Caffeine, on Recognition Memory and Striatal Monoamine Neurochemistry in Male Sprague Dawley Rats: Comparisons with Methamphetamine and Cocaine

Recent data suggest that 3,4-methylenedioxypyrovalerone (MDPV) has neurotoxic effects; however, the cognitive and neurochemical consequences of MDPV self-administration remain largely unexplored. Furthermore, despite the fact that drug preparations that contain MDPV often also contain caffeine, little is known regarding the toxic effects produced by the co-use of these two stimulants. The current study investigated the degree to which self-administered MDPV or a mixture of MDPV+caffeine can produce deficits in recognition memory and alter neurochemistry relative to prototypical stimulants. Male Sprague Dawley rats were provided 90 min or 12 h access to MDPV, MDPV+caffeine, methamphetamine, cocaine, or saline for 6 weeks. Novel object recognition (NOR) memory was evaluated prior to any drug self-administration history and 3 weeks after the final self-administration session. Rats that had 12 h access to methamphetamine and those that had 90 min or 12 h access to MDPV+caffeine exhibited significant deficits in NOR, whereas no significant deficits were observed in rats that self-administered cocaine or MDPV. Striatal monoamine levels were not systematically affected. These data demonstrate synergism between MDPV and caffeine with regard to producing recognition memory deficits, highlighting the importance of recapitulating the manner in which drugs are used (e.g., in mixtures containing multiple stimulants, binge-like patterns of intake).

Cardiovascular and Locomotor Effects of Binary Mixtures of Common "Bath Salts" Constituents: Studies with Methylone, MDPV, and Caffeine in Rats

Background and Purpose

The use of "Bath Salts" drug preparations has been associated with high rates of toxicity and death. Preparations often contain mixtures of drugs including multiple synthetic cathinones or synthetic cathinones and caffeine; however, little is known about whether interactions among "Bath Salts" constituents contribute to the adverse effects often reported in users.

Experimental Approach

This study used adult male Sprague-Dawley rats to characterize the cardiovascular effects, locomotor effects, and pharmacokinetics of methylone, MDPV, and caffeine, administered alone and as binary mixtures. Dose-addition analyses were used to determine the effect levels predicted for a strictly additive interaction for each dose pair.

Key Results

Methylone, MDPV, and caffeine increased heart rate and locomotion, with methylone producing the largest increase in heart rate, MDPV producing the largest increase in locomotor activity, and caffeine being the least effective in stimulating heart rate and locomotor activity. MDPV and caffeine increased mean arterial pressure, with caffeine being more effective than MDPV. The nature of the interactions between methylone and MDPV tended toward sub-additivity for all endpoints, whereas interactions between MDPV or methylone and caffeine tended to be additive or sub-additive for cardiovascular endpoints, and additive or supra-additive for increases in locomotion. No pharmacokinetic interactions were observed between individual constituents, but methylone displayed non-linear pharmacokinetics at the largest dose evaluated.

Conclusion and Implications

These findings demonstrate that the composition of "Bath Salts" preparations can impact both cardiovascular and locomotor effects and suggest that such interactions among constituent drugs could contribute to the "Bath Salts" toxidrome reported by human users.

Impacts of Self-Administered 3,4-Methylenedioxypyrovalerone (MDPV) Alone, and in Combination with Caffeine, on Recognition Memory and Striatal Monoamine Neurochemistry in Male Sprague-Dawley Rats: Comparisons with Methamphetamine and Cocaine

Recent data suggest that 3,4-methylenedioxypyrovalerone (MDPV) has neurotoxic effects; however, the cognitive and neurochemical consequences of MDPV self-administration remain largely unexplored. Furthermore, despite the fact that drug preparations that contain MDPV often also contain caffeine, little is known regarding the toxic effects produced by the co-use of these two stimulants. The current study investigated the degree to which self-administered MDPV, or a mixture of MDPV+caffeine can produce deficits in recognition memory and alter neurochemistry relative to prototypical stimulants. Male Sprague-Dawley rats were provided 90-min or 12-h access to MDPV, MDPV+caffeine, methamphetamine, cocaine, or saline for 6 weeks. Novel object recognition (NOR) memory was evaluated prior to any drug self-administration history and 3 weeks after the final self-administration session. Rats that had 12-h access to methamphetamine and those that had 90-min or 12-h access to MDPV+caffeine exhibited significant deficits in NOR, whereas no significant deficits were observed in rats that self-administered cocaine or MDPV. Striatal mono-amine levels were not systematically affected. These data demonstrate synergism between MDPV and caffeine with regard to producing recognition memory deficits and lethality, highlighting the importance of recapitulating the manner in which drugs are used (e.g., in mixtures containing multiple stimulants, binge-like patterns of intake).

Pharmacology of Drugs Used as Stimulants

Psychostimulant, cardiovascular, and temperature actions of stimulants involve adrenergic (norepinephrine), dopaminergic (dopamine), and serotonergic (serotonin) pathways. Stimulants such as amphetamine, 3,4-methylenedioxymethamphetamine (MDMA), or mephedrone can act on the neuronal membrane monoamine transporters NET, DAT, and SERT and/or the vesicular monoamine transporter 2 to inhibit reuptake of neurotransmitter or cause release by reverse transport. Stimulants may have additional effects involving pre- and postsynaptic/junctional receptors for norepinephrine, dopamine, and serotonin and other receptors. As a result, stimulants may have a wide range of possible actions. Agents with cocaine or MDMA-like actions can induce serious and potentially fatal adverse events via thermodysregulatory, cardiovascular, or other mechanisms. MDMA-like stimulants may cause hyperthermia that can be life threathening. Recreational users of stimulants should be aware of the dangers of hyperthermia in a rave/club environment.

Discriminative stimulus effects of 3,4-methylenedioxypyrovalerone (MDPV) and structurally related synthetic cathinones

The 3,4-methylenedioxypyrovalerone (MDPV), and other structurally related synthetic cathinones, are popular alternatives to prototypical illicit psychostimulants, such as cocaine and methamphetamine. These drugs are often referred to as 'bath salts' and function either as cocaine-like inhibitors of monoamine uptake, or amphetamine-like substrates for dopamine, norepinephrine and serotonin transporters. These studies used male Sprague-Dawley rats trained to discriminate MDPV from saline to evaluate the substitution profiles of structurally related synthetic cathinones, cocaine, and other direct-acting dopamine and noradrenergic receptor agonists in order to characterize the relative contributions of dopamine, norepinephrine and serotonin to the discriminative stimulus effects of MDPV. As expected, each of the cathinones and cocaine dose-dependently increased MDPV-appropriate responding, with a rank-order potency that was positively correlated with their potency to inhibit dopamine and norepinephrine, but not serotonin, a relationship that is consistent with the rank order to maintain self-administration. The dopamine D2/3 receptor-preferring agonist quinpirole produced a modest increase in MDPV-appropriate responding, whereas the dopamine D1/5 receptor agonist, SKF 82958, nonselective dopamine receptor agonist, apomorphine, as well as the α-1, and α-2 adrenergic receptor agonists, phenylephrine and clonidine, respectively, failed to increase MDPV-appropriate responding at doses smaller than those that suppressed responding altogether. Although these studies do not support a role for serotonergic or adrenergic systems in mediating/modulating the discriminative stimulus effects of MDPV, convergent evidence is provided to suggest that the discriminative stimulus effects of MDPV are primarily mediated by its capacity to inhibit dopamine uptake, and the subsequent activation of dopamine D2 or D3 receptors.

Interactive effects of (±)-trans-U50488 and its stereoisomers with cannabinoids

The adverse effects of mu opioid agonists have spurred a renewed interest in using kappa opioid receptor (KOR) agonists as analgesics. KOR agonists also have potential for development as diuretics for the treatment of edema and hypertension. Here, we evaluated the discriminative stimulus, antinociceptive, and diuretic effects of the kappa agonist (±)-trans-U-50488 and its stereoisomers (-)-(1S,2S)-U-50488 or (+)-(1R,2R)-U-50488) alone and in combination with the cannabinoid agonist (-)-CP 55,940. To establish (±)-U-50488 as a discriminative stimulus, rats (n = 12) were trained to discriminate intraperitoneal (i.p.) administration of 5.6 mg/kg of (±)-trans-U-50488 from saline under a fixed-ratio 20 (FR-20) schedule of food reinforcement. Then, antinociception was assessed using two procedures: warm water tail withdrawal and von Frey paw withdrawal. Diuretic effects were assessed in separate rats (n = 6/group). Doses of (±)-U-50488 and (-)-U-50488 that served as discriminative stimuli produced significant increases in urine output, but at lower doses than those that produced antinociception. In contrast, (+)-U-50488 alone had no discriminative stimulus or diuretic effects at the doses tested, but did produce antinociception in the von Frey assay. When three cannabinoids and morphine were tested in the (±)-U-50488 discrimination procedure to determine the similarity of these drugs' discriminative stimulus effects to those for (±)-U-50488, the rank order similarity was (-)-CP 55,940 > (-)-trans-THC > (+)-WIN 55,212-2 ≥ morphine. (-)-CP 55,940 alone (0.056 mg/kg) partially substituted for the discriminative stimulus effects of (±)-U-50488 and produced significant diuretic and antinociceptive effects. (-)-CP 55,940 in combination with (±)-U-50488 also produced a two-fold leftward shift in the discriminative stimulus curve for (±)-U-50488, and near-additive antinociception with (±)-U-50488 and (+)-U-50488. Further, the diuretic effect of (-)-CP 55,940 was enhanced by a dose of (+)-U50488, which itself did not alter urine output. These data together indicate that a combination of cannabinoid and kappa opioid agonists can enhance diuresis, but may have limited potential for serving as opioid-sparing pharmacotherapeutics for treatment of pain.

Methylenedioxymethamphetamine-like discriminative stimulus effects of seven cathinones in rats

Synthetic cathinone derivatives are commonly considered quasi-legal alternatives for stimulant drugs, such as cocaine and methamphetamine, but some derivatives are increasingly being detected in club drug formulations of Ecstasy or 'Molly' as substitutes for methylenedioxymethamphetamine (±-MDMA). Although several studies have evaluated the psychostimulant-like effects of synthetic cathinones, few cathinone compounds have been assessed for MDMA-like activity. In order to determine their likelihood of interchangeability with entactogenic club drugs, the discriminative stimulus effects of methcathinone, 4-fluoromethcathinone, 4-methylmethcathinone, 4-methylethcathinone, 3-fluoromethcathinone, pentedrone, and ethylone were assessed in Sprague-Dawley rats trained to discriminate 1.5 mg/kg racemic methylenedioxymethamphetamine (±-MDMA) from vehicle. Methamphetamine and the cathinones 4-fluoromethcathinone, 4-methylmethcathinone, 4-methylethcathinone, 3-fluoromethcathinone, pentedrone, and ethylone fully substituted for the discriminative stimulus effects of ±-MDMA. In contrast, methcathinone produced a maximum of only 43% ±-MDMA-appropriate responding and higher doses suppressed responding. Most, but not all of the cathinone compounds tested have discriminative stimulus effects similar to those of MDMA as well as psychostimulant-like effects; however, the potency of MDMA versus psychostimulant substitution varies substantially among the compounds, suggesting that a subset of synthetic cathinones are more MDMA-like than psychostimulant-like. These findings further highlight the highly-variable pharmacology of this class of compounds and suggest that those cathinones with MDMA-like effects may also have increased use as club drugs.

Methylenedioxymethamphetamine-like discriminative stimulus effects of pyrrolidinyl cathinones in rats

BACKGROUND

Synthetic cathinone derivatives are used as alternatives both for stimulant drugs such as cocaine and methamphetamine and for club drugs such as 3,4-methylenedioxymethamphetamine (MDMA), but little is known about their MDMA-like subjective effects.

METHODS

In order to determine their similarity to MDMA, the discriminative stimulus effects of 10 pyrrolidinyl cathinones (α-pyrrolidinopropiophenone, 4'-methyl-α-pyrrolidinopropiophenone (4'-MePPP), α-pyrrolidinobutiophenone, 3',4'-methylenedioxy-α-pyrrolidinobutyrophenone (MD-PBP), α-pyrrolidinovalerophenone, 3,4-methylenedioxy-pyrovalerone (MDPV), α-pyrrolidinopentiothiophenone, napthylpyrovalerone (naphyrone), α-pyrrolidinohexiophenone, and 4'-methyl-α-pyrrolidinohexiophenone (4'-MePHP)) were assessed in Sprague-Dawley rats trained to discriminate 1.5 mg/kg racemic ±-MDMA from vehicle.

RESULTS

Compounds with no substitutions on the phenyl ring and the thiophene produced 44-67% MDMA-appropriate responding. In contrast, the substituted pyrrolidinyl cathinones produced a range of MDMA-appropriate responding dependent upon the length of the alpha side chain. 4'-MePPP, with a single carbon on the alpha position, produced 99.8% MDMA-appropriate responding, MD-PBP (two carbons) produced 83%, naphyrone (three carbons) produced 71%, MDPV (three carbons) produced, 66%, and 4'-MePHP (four carbons) produced 47%.

CONCLUSIONS

Many cathinone compounds have discriminative stimulus effects similar to those of MDMA. However, the pyrrolidine substitution appears to reduce serotonergic effects, with a commensurate decrease in MDMA-like effects. Substitutions on the phenyl ring appear to be able to restore MDMA-like responding, but only in compounds with short alpha side chains. These findings agree with earlier findings of increasing dopaminergic effects and stronger reinforcing effects with increasing side chain. Assessment of more compounds is necessary to establish the replicability/robustness of this phenomenon. These findings may be of use in predicting which compounds will have MDMA/club drug-like effects versus psychostimulant-like effects.

Mephedrone Impact on Matrix Metalloproteinases Activity - Do they Influence the Memory Processes?

BACKGROUND

The use of drugs of addiction, as mephedrone, is associated with functional neuronal disorders due to remodeling of the nervous tissue. Key enzymes in remodeling are extracellular matrix (ECM) proteases like matrix metalloproteases (MMPs). Recently, MMPs have been of great interest as some studies point to a fact that the alterations in structural remodeling of synaptic connections modify learning-dependent changes, which remain active even after a prolonged period of abstinence. This entails a continuous development of dependence.

OBJECTIVES

The aim of the study was to determine the influence of subchronic exposure to three different doses of mephedrone on the activity of MMP-2 and 9 in hippocampus and prefrontal cortex and how this was correlated with memory processes in mice.

METHODS

The homogenates of hippocampus and cortex were assayed for MMP-2 and MMP-9 activity by gelatin zymography. Memory consolidation processes were evaluated in the passive avoidance (PA) test.

RESULTS

The study confirmed the dose-dependent increase in activity of MMP-2 and -9 exerted by subchronic administration of mephedrone. Moreover, the highest dose of mephedrone attenuated consolidation of memory and learning processes.

CONCLUSIONS

We could hypothesize that inhibition of MMPs can be considered as a therapeutic option for the treatment of addictive behaviors associated with cognitive processes. Moreover, further studies are required to find out if elevated activities of MMPs contribute to brain damage or recovery from brain damage caused directly by mephedrone.

Effects of cocaine on the discriminative stimulus and reinforcing effects of mephedrone in male rats

RATIONALE

Abuse of cathinones has been a worldwide health concern for some time. Their chemical structures and wide variation in pharmacodynamic effects have led to clinical and preclinical effects that can be both similar to and different from other psychoactive substances such as methylenedioxymethamphetamine (MDMA), methamphetamine, and cocaine.

OBJECTIVE

The present study examined the discriminative stimulus and reinforcing effects of mephedrone to further characterize the behavioral and pharmacological profile of this first-generation substituted methcathinone.

METHODS

Rats were trained to discriminate mephedrone (3.2 mg/kg) from saline under a fixed-ratio 20 (FR-20) schedule of food presentation. After establishing dose-effect curves for increasing cumulative doses of mephedrone, substitution tests were conducted with bupropion (5.6-32 mg/kg), cocaine (1.8-18 mg/kg), morphine (0.56-10 mg/kg), and amitriptyline (3.2-32 mg/kg). In addition, cocaine (3.2-18 mg/kg) and the serotonin type-2 (5-HT2) receptor antagonist ritanserin (1, 3.2, and 10 mg/kg) were administered prior to the cumulative doses of mephedrone. Lastly, varying infusion doses of cocaine were substituted for mephedrone in subjects trained to self-administer mephedrone, and varying infusion doses of mephedrone were substituted for cocaine in subjects trained to self-administer cocaine to assess the importance of drug history on the reinforcing effects of mephedrone.

RESULTS

Of the drugs tested, cocaine had the highest level of mephedrone-lever responding when administered alone (73.5%). In combination with mephedrone, cocaine shifted the mephedrone dose-effect curve upwards in an infra-additive manner. Ritanserin had a small, but non-significant, effect on mephedrone's discriminative stimulus effects. An extensive history (baseline) of cocaine self-administration increased mephedrone self-administration compared to that obtained in mephedrone-trained subjects, whereas a baseline of mephedrone self-administration decreased cocaine self-administration compared to that obtained in cocaine-trained subjects.

CONCLUSION

The similarity between the discriminative stimulus effects of cocaine and mephedrone in male rats suggests an important overlap and the relative importance of the dopamine (DAT) and serotonin (SERT) transporters. The self-administration data suggest that mephedrone is less reinforcing than cocaine, but that a history of responding for cocaine can increase the reinforcing effects of mephedrone.

Effects of dopaminergic and serotonergic compounds in rats trained to discriminate a high and a low training dose of the synthetic cathinone mephedrone

RATIONALE

The underlying pharmacological mechanisms of mephedrone, especially as related to interactions with different neurotransmitter systems, are a critical area of study as mephedrone continues to be abused.

OBJECTIVE

Direct-acting 5-HT_2A/2C receptor agonists and antagonists and D_1-3 receptor antagonists were examined in two groups of rats trained to discriminate mephedrone. A high dose of mephedrone was trained to extend previous results with traditional monoamine transporter inhibitors and substrate releasers. A very low dose of mephedrone was trained to preferentially capture serotonergic activity and to minimize the influence of rate-decreasing effects on substitution patterns. Selective 5-HT_2A/2C and D_1-3 receptor antagonists were examined in both groups.

METHODS

Male Sprague-Dawley rats were trained to discriminate either a low dose of 0.5 mg/kg mephedrone (N = 24) or a high dose of 3.2 mg/kg mephedrone (N = 11) from saline.

RESULTS

In the low training-dose group, mephedrone, MDMA, methamphetamine, d-amphetamine, cocaine, and enantiomers of mephedrone substituted for mephedrone; mCPP partially substituted overall for mephedrone; and DOI, WAY163909, and morphine failed to substitute for mephedrone. In the high training-dose group, only mephedrone and MDMA substituted for mephedrone. Sulpiride produced a small antagonism of the low training dose of mephedrone while SCH23390, SB242084, and ketanserin altered response rates.

CONCLUSIONS

A lower training dose of mephedrone produces a discriminative stimulus fully mimicked by MDMA, methamphetamine, cocaine, and d-amphetamine, whereas a higher training dose of mephedrone requires a discriminative stimulus that was only mimicked by MDMA. Dopaminergic or serotoninergic antagonists failed to produce significant blockade of mephedrone at either training dose.

Potential pro-oxidative effects of single dose of mephedrone in vital organs of mice

BACKGROUND

Mephedrone is a recreationally used synthetic cathinone, relatively new abusive substances with molecular structure similar to amphetamine. As there is still lack of scientific data regarding mechanisms of action as well as metabolism of mephedrone, especially in aspects other than neurotoxicity, addiction or behavioral changes, therefore we aimed, for the first time, to investigate potential pro-oxidative actions of a single dose of mephedrone in organs other than brain and its structures, i.e. in liver, kidneys, heart and spleen of Swiss mice.

METHODS

The following biomarkers of oxidative stress were measured: concentration of ascorbic acid (AA) and malondialdehyde (MDA) as well as total antioxidant capacity (TAC) of the tissues homogenates.

RESULTS

Our study revealed that mephedrone intoxication induces oxidative stress by reducing concentration of AA and TAC and increasing concentration of MDA in these organs.

CONCLUSIONS

Such occurred state of antioxidant-oxidant imbalance may be etiopathological factor of a number of severe diseases within cardiovascular, digestive as well as immunological systems.

Evaluating the abuse potential of psychedelic drugs as part of the safety pharmacology assessment for medical use in humans

Psychedelics comprise drugs come from various pharmacological classes including 5-HT_2A agonists, indirect 5-HT agonists, e.g., MDMA, NMDA antagonists and κ-opioid receptor agonists. There is resurgence in developing psychedelics to treat psychiatric disorders with high unmet clinical need. Many, but not all, psychedelics are schedule 1 controlled drugs (CDs), i.e., no approved medical use. For existing psychedelics in development, regulatory approval will require a move from schedule 1 to a CD schedule for drugs with medical use, i.e., schedules 2-5. Although abuse of the psychedelics is well documented, a systematic preclinical and clinical evaluation of the risks they pose in a medical-use setting does not exist. We describe the non-clinical tests required for a regulatory evaluation of abuse/dependence risks, i.e., drug-discrimination, intravenous self-administration and physical dependence liability. A synopsis of the existing data for the various types of psychedelics is provided and we describe our findings with psychedelic drugs in these models. FDA recently issued its guidance on abuse/dependence evaluation of drug-candidates (CDER/FDA, 2017). We critically review the guidance, discuss the impact this document will have on non-clinical abuse/dependence testing, and offer advice on how non-clinical abuse/dependence experiments can be designed to meet not only the expectations of FDA, but also other regulatory agencies. Finally, we offer views on how these non-clinical tests can be refined to provide more meaningful information to aid the assessment of the risks posed by CNS drug-candidates for abuse and physical dependence. This article is part of the Special Issue entitled 'Psychedelics: New Doors, Altered Perceptions'.

Evaluation of training dose in male Sprague-Dawley rats trained to discriminate 4-methylmethcathinone

RATIONALE

Although the synthetic cathinone 4-methylmethcathinone (4-MMC, mephedrone) has been a subject of intensive research investigation, the pharmacological mechanisms involved in its interoceptive stimulus effects have yet to be fully characterized.

OBJECTIVE

The present study employed drug discrimination methods in rats to compare the interoceptive stimulus properties of two different training doses of 4-MMC to other substances with similar pharmacological actions.

METHODS

Sixteen male Sprague-Dawley rats were trained to discriminate either 1.0 mg/kg (N = 8) or 3.0 mg/kg (N = 8) 4-MMC from saline. Substitution tests were conducted with drugs that increase extracellular monoamine levels (d-amphetamine, (+)-methamphetamine, 4-MMC, MDMA, MDPV, and (-)-cocaine), a serotonin releaser (+)-fenfluramine, and a serotonergic (5-HT_2A) hallucinogen (+)-LSD.

RESULTS

Stimulus control was established in fewer sessions in the subjects trained with 3.0 mg/kg compared to those trained with 1.0 mg/kg 4-MMC. Cocaine, MDMA, and d-amphetamine produced full substitution in the 1.0 mg/kg 4-MMC-trained rats at doses that did not decrease response rate. However, doses of test drugs that engendered > 80% 4-MMC-lever selection concurrently produced rate-decreasing effects in rats trained to discriminate 3.0 mg/kg 4-MMC.

CONCLUSIONS

These findings further characterize the interoceptive stimulus effects of 4-MMC and indicate that these effects vary little with training dose; however, qualitative differences in substitutability of test drugs were observed between training groups. This study expands existing knowledge regarding the psychopharmacology of 4-MMC and the potential neurochemical substrates contributing to its subjective effects.

The pharmacokinetic profile of synthetic cathinones in a pregnancy model

In recent years, the abuse of synthetic cathinones or 'bath salts' has become a major public health concern. Although these compounds were initially sold legally and labeled "not for human consumption", the 'bath salts' are psychostimulants, with similar structures and pharmacologic mechanisms to cocaine, the amphetamines, and 3,4 methylendioxymethamphetamine (MDMA, Molly, or Ecstasy). The reported use of these substances by women of child-bearing age highlights the necessity of studies seeking to delineate risks of prenatal exposure. Three popular drugs of this type are methylone, mephedrone, and 3, 4-methylenedioxypyrovalerone (MDPV). Unfortunately, there is currently no information available on the teratogenicity of these compounds, or of the extent to which they cross the placenta. As such, the purpose of this study was to examine the pharmacokinetic profile of the 'bath salts' in a pregnancy model. Pregnant mice (E17.5 gestation) were injected intraperitoneally with a cocktail of 5mg/kg methylone, 10mg/kg mephedrone, and 3mg/kg (MDPV) dissolved in sterile saline. Maternal brain, maternal plasma, placenta, and fetal brain were collected at 30s, 1min, 5min, 10min, 15min, 30min, 1h, 2h, 4h, and 8h following injection. Methylone, mephedrone, and MDPV were extracted from tissue by solid phase extraction, and concentrations were determined using a previously validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. Interestingly, all 3 cathinones reached measurable concentrations in the placenta, as well as the fetal brain; in fact, for MDPV, the maximal concentration (Cmax) was highest in fetal brain, while mephedrone's highest Cmax value was achieved in placenta. Additionally, the total drug exposure for all 3 compounds (as represented by area under the curve, AUC) was higher in fetal matrices (placenta and fetal brain) than in maternal matrices (maternal brain and plasma), and the half-lives for the drugs were longer. Given the extensive presence of methylone, mephedrone, and MDPV in the fetal brain following prenatal exposure, fetal risk is definitely a concern. As there are currently no prenatal studies available on the teratogenicity of these agents, pregnant patients should be informed about the potential risks that these substances may have.