Tuesday, September 11, 2012

Can rats "tell us" they want methamphetamine by "talking"?

A research group at the Medical University of South Carolina recently published a paper in the journal Behavioural Brain Research on ultrasonic vocalizations (USVs) and methamphetamine self-administration.  Rats were trained to make a response to receive a methamphetamine infusion, but then responses did not yield drug delivery.  The authors observed differences in vocalizations from when methamphetamine was available and when it was not available.  Moreover, different vocalizations were observed when cues associated with methamphetamine were presented, than when other cues were presented.  These data suggest drug addiction researchers could use USVs to study the subjective states (e.g., "craving") associated with methamphetamine reinforcement.

Reference - S.V. Mahler et al. (2012) A rodent “Self-Report” measure of methamphetamine craving? Rat ultrasonic vocalizations during methamphetamine self-administration, extinction, and reinstatement . Behavioural Brain Research  , in press.

Wednesday, June 20, 2012

"Bath Salts" and methamphetamine have a different toxicological profile?

There have been a number of news reports recently about people who display abnormal aggression while using "bath salts".  The putative active ingredient in these preparations is mephedrone, a combination of methamphetamine and cathinone.  While methamphetamine is neurotoxic to the terminal button of striatal neurons, a report in The Journal of Neurochemistry suggests that mephedrone lacks methamphetamine's impact in this model.   Despite the similarities between mephedrone and methamphetamine, mephedrone does not produce methamphetamine's change in dopamine, dopamine transporter, or tyrosine hydroxylase.

Reference - Angoa-Perez et al. (2012). Mephedrone, an abused psychoactive component of 'bath salts' and methamphetamine congener, does not cause neurotoxicity to dopamine nerve endings of the striatum  J Neurosci 120(6): 1097

Sunday, June 17, 2012

New volume on methamphetamine abuse, health effects and treatment

Our research group at the University of Missouri has contributed chapters to a new book on methamphetamine (Methamphetamines: Abuse, Health Effects, and Treatment Options.  Nova Science Publishers).  Our chapters focused on methamphetamine's mechanism of action in the brain, using locomotor activity in rodents to study the drug, and sigma receptors as a possible treatment for methamphetamine abuse.

Reference- Methamphetamines: Abuse, Health Effects, and Treatment Options. J Ornoy & X. He, Eds., Nova Science Publishers, 2012.

Dextromethorphan diminishes methamphetamine's effects

Dextromethorphan is a cough suppressant found in Robitussin-DM and Mucinex-DM and binds to a number of sites in the brain related to drug abuse and dependence, including opioid receptors, sigma receptors, glutamate receptors and neurotransmitter transporters.  Pao-Pao Yang and colleagues recently published a research article in the journal Synapse indicating that dextromethorphan could be a treatment for craving for methamphetamine craving.  In their experiment, dextromethorphan microinjection into brain regions associated with drug abuse and dependence (the nucleus accumbens and ventral tegmental area) decreased methamphetamine-seeking during a methamphetamine withdrawal period.

Reference - Yang PP et al (2012) Post-treatment of dextromethorphan on methamphetamine-induced drug-seeking and behavioral sensitization in rats. Synapse

Thursday, April 5, 2012

Legalize abused drugs, including methamphetamine?

In The Washington Post yesterday morning, George Will comments on drug legalization.  He doesn't specifically mention methamphetamine--the focus is on cocaine and marijuana--but, is legalization or decriminalization of methamphetamine a viable policy?

Reference: Will GF, The legalization dilemma, The Washington Post, April 4, 2012

Tuesday, February 28, 2012

Donepezil (Aricept) blocks cocaine's, but not methamphetamine's, effects

Donepezil is used to manage the early symptoms of Alzheimer's Disease and is available as the Aricept preparation.  It is a cholinesterase inhibitor, and increases acetylcholine levels in brain.  Our lab group recently reviewed a paper by Takamatsu and colleages on donepezil's efficacy to block the conditioned reinforcing (place preference) and locomotor activating properties of cocaine and methamphetamine in mice.  While it diminished the effects of cocaine, it was ineffective to alter methamphetamine's effects in this study.  Considering the efficacy of other cholinergic ligands (e.g., lobeline) to alter methamphetamine's effects, these findings were surprising to us.

Reference - Takamatus Y. et al. (2006) Differential effects of donepezil on methamphetamine and cocaine depedencies.  Ann NY Acad Sci 1074: 418

Thursday, February 23, 2012

Methamphetamine place preference

Our laboratory at the University of Missouri is working to develop a place preference assay to evaluate the conditioned-rewarding properties of methamphetamine in mice.  We were able to develop a cocaine place preference procedure, but have been struggling with methamphetamine.  Any suggestions would be appreciated!

Associated Press - National Meth Lab Busts Up in 2011

From the Associated Press...

Methamphetamine lab seizures rose nationally again in 2011, further evidence that the powerfully addictive and dangerous drug is maintaining a tight grip on the nation's heartland, according to an Associated Press survey of the nation's top meth-producing states.

Do these findings reflect a decrease in methamphetamine use nationwide?

Reference - National Meth Lab Busts Up in 2011. Jim Salter, Associated Press cited in the Columbia Missourian, Feb. 22,2012

Modafinil for the treatment of methamphetamine abuse?

In a recent  article in the journal Drug and Alcohol Dependence Ann L. Anderson and colleagues evaluated the efficacy of the psychostimulant modafinil as a treatment for methamphetamine abuse. This was a relatively-large study of patients dependent on methamphetamine who received (double-blind design) modafinil (200 or 400 mg) or placebo over twelve weeks.  Despite the animal research that suggests that modafinil could block or replace methamphetamine's "addictive" effects, there was no significant impact of modafinil treatment on methamphetamine use in these patients.  The authors suggest a problem was that the patients did not comply with the modafinil treatment regimen.

Reference - Modafinil for the Treatment of Methamphetamine Dependence, A.L. Anderson, et. al. (2012) Drug & Alcohol Dependence 120: 135.