TL neuro

December 9, 2016

Vaccination against the effects of MDPV (“bathsalts”) and alpha-PVP (“flakka”)

Filed under: alpha-PVP, Cathinones, MDPV, Vaccines — mtaffe @ 10:10 am

The substituted cathinone stimulants 3,4-methylenedioxypyrovalerone (MDPV) and alpha-pyrrolidinopentiophenone(alpha-PVP) have emerged as significant public health concerns in recent years. These drugs turned out to be monoamine transporter inhibitors with high selectivity for the dopamine transporter. These two compounds lack the monoamine releasing properties of methamphetamine, MDMA and other recently popular cathinone derivatives such as mephedrone and methylone. As we’ve shown, both MDPV and alpha-PVP are highly reinforcing in the rat self-administration paradigm and increase locomotor behavior when injected non-contingently or inhaled with e-cig technology. Although these drugs are still in the early stages of market penetration, the data from our lab as well as several other labs suggest that these will have high abuse liability. Effective countermeasures are therefore likely to be needed in the future.

One method to counteract effects of psychoactive drugs that has been attempted is vaccination; an explainer video from NIDA is available here. In this strategy a drug-like chemical structure is attached to a large protein that generates an immune response. When successful, this immune response creates antibodies that circulate in the blood with the capacity to recognize and bind to the target drug molecule. If this is done to effective levels, the administration of a given dose of drug leads to a reduced response, due to part of the drug dose being bound to antibodies in the bloodstream which prevents from entering the brain.

A paper describing an initial effort to develop a vaccine to provide protection against the effects of MDPV and alpha-PVP has recently been accepted for publication. As with all of our vaccine work to date, this was conducted in collaboration with the Janda laboratory at TSRI.

Nguyen, J.D., Bremer, P.T., Ducime, Creehan, K.M., Kisby, B.R., Taffe, M.A. and Janda, K.D. Active vaccination attenuates the psychostimulant effects of α-PVP and MDPV in rats, Neuropharmacology, 2017, 116:1-8. [PubMed][Publisher Site]

In this study, Paul Bremer and Alex Ducime created vaccine candidates designed to generate antibodies against MDPV and alpha-PVP, respectively. Initially, three groups of male rats were vaccinated to evaluate the MDPV-specific, alpha-PVP-specific vaccines against a group vaccinated with the immunogenic protein (keyhole limpet hemocyanin; KLH). The antibodies in the MDPV-vaccinated group showed high affinity for MDPV but not for alpha-PVP or methamphetamine. Likewise, the antibodies in the alpha-PVP group were selective for alpha-PVP over MDPV or methampetamine.

Brent Kisby, an undergraduate on an extended internship, in combination with Kevin Creehan and Jacques Nguyen first determined if these rats would exhibit functional protection against drug exposure. We selected a wheel-activity response to drug injection (see Huang et al, 2012) because this had proved effective at screening anti-methamphetamine candidate vaccines in our prior study (Miller et al, 2013).
nguyen17-alphavaccfig3-wheel This figure (click to enlarge) shows wheel activity (quarter revolutions) in the four hours following injection with four doses of alpha-PVP (Panels A, B) or four doses of MDPV (Panels C, D). The left hand panels depict the effects of drug in the KLH-only control groups while the right hand panels depict the effects of drug in the respective alpha-PVP-KLH and MDPV-KLH vaccine groups. The asterix indicates a significant change of activity relative to the vehicle (saline) injection condition. The takeaway message here is that doses of alpha-PVP (0.5, 1.0 mg/kg, i.p.) and MDPV (1.0 mg/kg, i.p.) which increase wheel activity in the control group do not do so in the respective vaccine group. The vaccine can be partially surmounted since the 5 mg/kg dose of each drug increased activity in the vaccinated rats, although this increase was numerically lower and lasted less long in the MDPV-KLH and alpha-PVP-KLH animals compared with the control group.

This promising result led to the design of an intravenous self-administration study to test the ability of alpha-PVP-KLH vaccination to alter the course of self-administration. Jacques Nguyen and Kevin Creehan headed up this study.
A group of rats were first trained to self-administer alpha-PVP, prior to any vaccination. This is only the second study to publish the acquisition of alpha-PVP self-administration in an animal model (see Aarde et al, 2015) and we found that a 0.1 mg/kg/infusion dose was required to produce good acquisition in Sprague-Dawley male rats. Thereafter the rats were placed on hiatus from drug self-administration and given a 5 week protocol of three immunizations, divided into two groups- one receiving KLH only and the other receiving alpha-PVP-KLH vaccine. We showed first that on return to self-administration at a reduced per-infusion dose of 0.025 mg/kg/infusion the alpha-PVP-KLH vaccinated animals self-administered more drug. This result is consistent with the circulating antibodies producing partial reduction of the dose as it was self-administered and the corresponding behavioral compensation to produce similar brain levels of drug.
nguyen17-fig7-prepostAfter three weeks the animals were given a booster immunization which resulted in about a doubling of the circulating antibody level (titer). This resulted in no change in the KLH-only animals’ drug intake, however the alpha-PVP-KLH animals changed from a mean of 17-20 infusions per session to a mean of about 4-5 infusions per session, a significant reduction in self administration. This lasted for 15 sessions and is depicted in the figure (click to enlarge) as Post4-Post8 bins of three sequential sessions.

As discussed in the paper this is an initial feasibility study but it shows the potential of the anti-drug immunotherapy strategy to be effective against the effects of both MDPV and alpha-PVP. This should encourage additional work to determine the extent and nature of the protection against these substituted cathinone stimulants that can be achieved with vaccines.

These studies were funded by USPHS grants DA024705, DA042211 and DA037709.
Additional Reading: A list of our cathinone-related publications can be found here.

December 3, 2016

New Chapter on Entactogen Self-Administration

Filed under: 4-MMC/Mephedrone, alpha-PVP, Cathinones, MDPV, Methylone — mtaffe @ 2:48 pm

We have recently published a short review on the self-administration of entactogen psychostimulants.

Aarde, S.M. and Taffe, M.A. Predicting the Abuse Liability of Entactogen-Class, New and Emerging Psychoactive Substances via Preclinical Models of Drug Self-administration. Curr Top Behav Neurosci. 2016 Dec 2. [Epub ahead of print] [PubMed][Publisher Site]

This is part of a Current Topics in Behavioral Neuroscience book on New and Emerging Psychoactive Substances organized by Mike Baumann of the NIDA IRP who has been publishing a lot of work on synthetic cathinones lately. Eventually the Chapters will be collected into a book and assigned unique pagination.

For now you can look chronologically in the pre-publication OnlineFirst list.

The first chapter of the series that was published was:
Schifano et al “NPS: Medical Consequences Associated with Their Intake” [link]

The cannabinoids are covered:
Wiley, Marusich and Thomas Combination Chemistry: Structure–Activity Relationships of Novel Psychoactive Cannabinoids [link]

All told there will be around a dozen chapters, I think most of them are on the pre-print list already. Happy reading!

July 16, 2015

UPROXX theTRUTH: About Bath Salts

Filed under: 4-MMC/Mephedrone, alpha-PVP, Cathinones, MDPV, Methylone, Public Health — mtaffe @ 11:36 am

The UPROXX folks were kind enough to invite me to make a clip on the synthetic cathinones for their new ‘theTRUTH’ series.

This was a novel experience for me and it was very difficult. If you look closely at this video and the ones linked below, you will notice how many cuts there are. The production team basically wants you to spit out very short and pithy statements which they can edit together into a whole. So it was conducted in a sort of interview style with a producer asking me questions and me responding as briefly as possible. Often times the same point had to be made several times to get it right. I even had to record a series of hand gestures and transitional phrases in case they needed to bridge points!

After that it was in their hands to stitch it together and tell a story. Obviously, one of the things I was trying to do was to not say anything that could be edited into a context that misrepresented anything too badly. On the whole, I think the UPROXX production team did a good job, given the material (me) they had to work with.

Others in this theTRUTH series include pieces on Toxoplasma gondii and large earthquakes.

May 31, 2015

A few notes on the CNN article on flakka

Filed under: alpha-PVP, Cathinones, MDPV — mtaffe @ 2:31 pm

A CNN article on flakka (alpha-PVP) is making the rounds.

What is flakka and why is it so dangerous?

I had a few observations on Facebook that I thought I’d repost here.

1) It is hard to control the exact dose of any street preparation. Flakka is not really any different from other drugs in this aspect.

2) “Just a little bit of difference” is a sloppy way to talk about a recreational index (analogous to therapeutic index), i.e., the distance between what gets you high and what kills you. No sign this is true for alpha-PVP…at all. Many drugs differ in potency and if you dose yourself with a mysterious powder expecting it to be Drug X and it is really a much more potent Drug Y, yes, your margin of error is perhaps less. But again, this isn’t specific to Alpha-PVP and for sure doesn’t differentiate it from MDPV (“bathsalts”).

3) “excited delirium” is a made up term used by law enforcement to justify when they kill someone who is acting violent and bizarre and, more importantly, fighting back when they try to physically restrain them. You should be very suspicious when this term is used, in my opinion. The violent behavior referenced here very likely is a consequence of the paranoia and attempts by law enforcement to restrain the individual. High muscle effort leads to elevated heat generation and therefore increases body temperature. It all comes back to the paranoia and the effects of law enforcement intervention. Not the drug.

4) “strength of ten men” nonsense, this time by reference to the cartoon icon The Hulk. Perhaps the drug causes a little bit of insensitivity to pain, that is understandable. And paranoid fighting for one’s life? perhaps. But drugs cannot magically increase muscular strength!

5) It is not at all clear that alpha-PVP has longer-lasting effects than methamphetamine and I would very much doubt this is true. Methamphetamine has a pretty long half-life. In our studies the locomotor stimulant effect of methamphetamine lasts longer than that of alpha-PVP or MDPV (although there are reports from the Gatch lab of 6 hr stimulant effects in mice). There have not been a lot of controlled studies so far, so I would argue that for dang sure this CNN statement on duration of effect of flake is not presently justified.

6) “it could destroy [neurons]”. Sure. but from what we know about the pharmacology, these transporter inhibitors, alpha-PVP and MDPV, are unlikely to represent the harm to dopaminergic and serotonergic neurons that is familiar from repeated methamphetamine or MDMA dosing. Methylone and mephedrone are much more likely to have these problems, by way of example. The Kuhn lab has a recent paper which shows a protective effect of MDPV. From their abstract “The β-ketoamphetamines [cathinones] alone or in all possible two-drug combinations do not result in damage to DA nerve endings but do cause hyperthermia. “.

7) kidneys- sure but one would expect this to be mostly a consequence of medical emergency featuring rhabdomyolysis, typically in cases of very high body temperature. Not by any means a typical effect.

8) Unclear if alpha-PVP is more dangerous than “bathsalts that came before it”. Well that’s a nice trite, unfalsifiable statement but going by the existing evidence (including our study) alpha-PVP and MDPV are going to be very similar in many aspects of the health dangers they might represent.

9) No, sellers cannot work around a DEA Schedule ban by putting “not for human consumption” on the packaging. This is just plain false. and it will not take years to ban flakka. It was placed on the Sched I list in a temporary action in early 2014. This has the same force as a permanent ban and there is every indication that this will be finalized.

C’mon CNN. You can do better than this.

additional comment from forensictoxguy

May 8, 2015

Press for the paper on flakka / alpha-PVP

Filed under: alpha-PVP, Cathinones, MDPV — mtaffe @ 8:35 am

TSRI did a Press Release on our recent papers describing the self-administration of alpha-PVP and MDPV and another paper on how MDPV self-administration supplants interest in wheel running.

It was posted to EurekAlert and the following sources picked it up and republished it, essentially as-is:



Medical Xpress


Jersey Tribune

Toronto Sun

David Bradley came up with a Breaking Bad style figure for his blog post reprint

Pieces for which we were interviewed:

Tech Times by Andrea Alfano

KPBS radio news brief by David Wagner

May 6, 2015

Methylone is replacing MDMA in Forensic Laboratory samples

Filed under: alpha-PVP, Cathinones, MDMA, MDPV, Methamphetamine, Methylone — mtaffe @ 10:38 am

The National Forensic Laboratory Information System (NFLIS) is, according to the Introduction to the 2014 Mid-year report [PDF]:

a program of the Drug Enforcement Administration (DEA), Office of Diversion Control NFLIS systematically collects results from drug analyses conducted by State and local forensic laboratories These laboratories analyze controlled and noncontrolled substances secured in law enforcement operations across the country, making NFLIS an important resource for monitoring illicit drug use

I was curious to see what this particular dataset had to say about the emergence of substituted cathinone stimulants such as mephedrone, methylone, MDPV and alpha-PVP. We work on the effects of these drugs and it is of interest to monitor the evolution of their use with various epidemiological measures. This is but one such measure and the relative penetration of a given drug may differ depending on whether the measure is from law enforcement, surveys of adolescents, online surveys, etc.

NFLIS-summaryThe NFLIS appears to have started systematically assessing several cathinone drugs in 2011. Either that or they were too infrequent to make the specific tables presented in the reports. These are relatively low incidence, you will note. For comparison, methamphetamine accounts for about 10% of reports and did not change much across 2010 to 2012 when MDMA reports dropped significantly. I would have predicted, before seeing these data, that the incidence of MDMA was still higher than these newer drugs. This figure shows that methylone is now more frequently reported in NFLIS samples than is MDMA. Methylone is probably the most MDMA-like of the cathinones in terms of structure (it is the direct cathinone cousin, 3,4-methylenedioxymethcathinone), neuropharmacology and subjective effects (to the extent this has been assessed).
The second surprise for me was seeing that MDPV and alpha-PVP are less commonly reported than methylone. I would have expected these drugs to have a higher representation, based on the emerging profile as traditional stimulants that support highly repetitive use.

h/t: Forensic Tox Guy

April 16, 2015

Alpha-PVP (“flakka”) and MDPV (“bathsalts”) are equivalently effective and potent

Filed under: alpha-PVP, Cathinones — mtaffe @ 8:50 am

In a prior post I briefly discussed the fact that alpha-PVP or “flakka” (sometimes “gravel”) has been in the news lately, due to being associated with bizarre behavior in users. A frequent theme of the news media reporting is that this drug is stronger or more dangerous than bathsalts. For examples see here, here, here, here. This one has the extra bonus of repeating the claim that the Causeway Cannibal was on bathsalts…forensic testing proved this initial claim from the police, repeated endlessly in the media, was not the case.

Structure-Pyrrolidine-MDPV-alphaPVPAs it happens, we conducted a study to compare these two drugs directly in rat models of locomotor stimulation, temperature disruption and self-administration. Alpha-PVP is structurally very similar to MDPV, as you can see in this figure. We were particularly intrigued by a report from Marusich et al (2014) which showed that alpha-PVP is less potent at inhibiting the dopamine transporter (a major pharmacological property of cocaine and the amphetamines) compared with MDPV. Correspondingly, the authors also showed alpha-PVP was less potent than MDPV in a mouse locomotor-stimulation test (but was able to increase locomotor activity to at least the same amount at a higher dose, showing similar efficacy). Another study by Naylor et al (2015) found that alpha-PVP fully substituted for methamphetamine in rats trained to distinguish methamphetamine from saline, but it was less potent than methamphetamine. We had previously shown [blog post, Aarde et al 2013, press account] that MDPV is more potent and effective than methamphetamine in rat self-administration. So initially we were predicting that MDPV would probably be more potent than alpha-PVP in a direct comparison study.

A description of our study has recently been accepted for publication:

Shawn M. Aarde, Kevin M. Creehan, Sophia A. Vandewater, Tobin J. Dickerson and Michael
A. Taffe. In vivo potency and efficacy of the novel cathinone α-pyrrolidinopentiophenone and 3,4-methylenedioxypyrovalerone: Self-administration and locomotor stimulation in male rats, 2015, Psychopharmacology, in press.
[PubMed, Publisher Link]

The study was conducted in separate groups of male rats originally trained to self-administer MDPV or alpha-PVP intravenously (0.05 mg/kg/inf in both cases) under a Fixed Ratio 1 contingency. This means each press of the drug-associated lever resulted in one drug infusion over the course of 20 sessions of 1 h duration. At the end of this interval the alpha-PVP rats were reaching mean intakes slightly higher than the MDPV rats, but these differences were mostly attributable to one or two animals in each group. The intake for the MDPV trained animals agreed quite well with our two previous studies [Aarde et al 2013, above; Aarde et al, 2014 Epub ahead of print] which involved a similar acquisition phase.

Fig5-MDPV-AlphaDR-PR-brkptforProgreportIn the following Progressive-Ratio dose-substitution procedure, the animals were permitted to respond for different infusion doses on different days. During the session within this procedure, each subsequent infusion of drug required an additional number of lever responses during the session. What I show in this figure (this study is represented by drug-associated lever-responses in the paper*) are the breakpoints achieved in a Progressive Ratio assay . The “breakpoint”, graphed here, reflects the mean number of responses required to obtain the final infusion the rats obtained on a given session. Doses were presented in random order across the groups (Significant differences from the 0.018 mg/kg/inf dose condition are signified by *, from the 0.032 dose by &, from the 0.056 dose by % and differences from the 0.56 dose by #.).

As should be obvious, MDPV and alpha-PVP generated remarkably similar behavior. The peaks of the two curves are about the same, indicting that the maximum reinforcing effect of these drugs is similar. The curves also overlap across the entire dose range, suggesting that the potency of the drugs is similar.

Aarde15-alphaPVP-MDPV-locomotorPeakAdditional data in the paper show that the doses of alpha-PVP and MDPV which produced the maximum locomotor stimulation, and the most body temperature alteration, after intraperitoneal injection were similar. Here we show the activity counts of a group of rats after injection of MDPV or alpha-PVP (at 1.0 mg/kg, i.p.) compared with when they were injected with the saline vehicle (in a reconfiguration of the published data). This shows that increases in activity rate were of about the same magnitude for each drug and that effects lasted up to about two hours. We had administered two higher doses of each drug and there was little evidence of any potency difference across the range of doses that we used. Administration of lower doses in pilot studies had established a similar lack of difference of the effect of the two drugs down to the lower bound of detectable effects.

Our prior studies showed very clearly that MDPV is a potent drug reward in the rat intravenous self-administration assay. The new study shows that alpha-PVP is equally potent and equally effective. We have no evidence that it is more potent or more effective than MDPV, however.

These studies were supported by a grant from the National Institutes of Health, National Institute on Drug Abuse (R01 DA024105.). The NIH/NIDA had no direct input on the study design, the interpretation of results or any choices with respect to publication of the results.

*because lever responses tend to be more normally distributed, unlike breakpoints, which aligns better with the assumptions of the inferential statistical technique we used to compare behavior.

Blog at