I am a second year PhD student in the BCaN program. I graduated from the University of Houston in 2012 with my BS in Psychology. During my undergraduate career I volunteered to work with both the Clinical Neuroscience Research Team led by Dr. Merrill Hiscock and the Behavioral Neuroscience Research Team directed by Dr. J. Leigh Leasure. In spring of 2013 I began working as a research technician in Dr. M. Waleed Gaber’s Pediatric Oncology/Radiation Research Lab through the Baylor College of Medicine at Texas Children’s Hospital in Houston, Texas. In the fall of 2015 I joined the Psychopharmacology Laboratory led by Dr. Anthony (Tony) L. Riley at American University in Washington, DC, as a Psychology Master’s Student in the Biological/Experimental thesis track. After successfully defending my Master’s thesis during the summer of 2017, I joined the doctoral program (PhD) in Behavior, Cognition and Neuroscience (BCaN) starting in the fall of 2017.
My goals in behavioral neuroscience at the moment involve understanding the way drugs affect behavior; including drug taking, use, and abuse, as well as researching factors that may influence addiction vulnerability. Some factors that may impact abuse liability include: age, sex, dose, route of administration, drug history, species, strain, concurrent and simultaneous drug use, among a large list of other factors. Most recently my work has been focused on characterizing the synthetic cathinones, specifically alpha-pyrrolidinopentiophenone (α-PVP) as well as its individual enantiomers. α-PVP is a psychostimulant that is cocaine-like in its mechanism of action in that it is a potent reuptake inhibitor for dopamine (DA)and norepinephrine (NE)but does not block the reuptake of serotonin (5-HT) and does not stimulate the release of these neurotransmitters (as is the case with amphetamine and amphetamine-like drugs).
Synthetic cathinones (i.e. “bath salts”, “research chemicals”, “legal highs” etc.) are man-made analogs of cathinone, a naturally derived amphetamine-like stimulant. Cathinone is found in the fresh leaves of the khat plant (Catha edulis) which is a small leafy green shrub native to eastern Africa (Ethiopia, Kenya, etc.) and the Arabian Peninsula where the leaves are chewed or brewed in teas for their mild stimulant effects.
Our lab predominantly focuses on the affective properties of these compounds. Drug use and abuse are thought to be a function of an affective balance, such that rewarding effects of the drug support intake while its aversive effects limit it. The studies I have performed recently have focused on behavioral assays that index these affective properties and employed designs such as conditioned taste avoidance (CTA) (assesses aversive qualities) and conditioned place preference (CPP) (assesses rewarding qualities). CTA takes advantage an animal’s tendency to avoid consumption of ordinarily preferred drug-paired solutions (i.e., water sweetened with saccharin), presumably due to an association between the taste (the conditioned stimulus, CS) and the drug’s aversive effects (the unconditioned stimulus, US). CPP is used as a measure for reward as the animal associates a distinct chamber with a drug’s rewarding effects and spends more time on the drug-paired side. These experimental designs are used both separately and in tandem (a combined CTA/CPP design) to assess the balance of reward and aversion associated with α-PVP, which are factors that ultimately impact the likelihood of self-administration – the gold standard in determining abuse potential in human users. In addition to these assays I have assessed the effects that α-PVP may have on hyperactivity and thermoregulation (effects that contribute to toxic reactions in humans, e.g., potentially fatal increases in body temperature and extreme tremor disorder).
A current project that is reaching completion involves researching the stereo-selective effects of α-PVP. Enantiomers are structural isomers of a molecule which are mirror images of each other that cannot be superimposed. Enantiomers can have differential effects. The goal of this project is to determine the relative contribution of each enantiomer of α-PVP in terms of their rewarding and aversive effects as well as their ability to induce hyperactivity and hyperthermia. This series of assessments took place at 3 doses: 1.5 mg/kg, 3.0 mg/kg, and 6.0 mg/kg. The middle dose (3.0 mg/kg) was based on previous work in our laboratory in which racemic α-PVP (a 50:50 preparation of both R and S enantiomers) induced a significant, but intermediate, suppression of saccharin consumption (see Nelson et al., 2017), allowing for assessments of the relative strength of conditioning by racemic α-PVP and its isomers. This experiment is expected to wrap up around fall 2018. Once we have more data collected, this project will be presented at future conferences and prepared for publication.
The most current study is assessing sex differences that builds off of the recently completed/nearing completion stereoisomer project. This is a straight forward comparison of male and female Sprague Dawley rats in a combined CTA/CPP design using the same doses as before (1.5, 3.0 and 6.0 mg/kg) of racemic α-PVP. The first replicate of this project is expected to last from the end of July to the end of October 2018 before repeating with more subjects.
Other projects are currently in the planning phases to assess: drug combinations, concurrent drug administration, simultaneous drug administration, self-administration, neurotoxicity, age differences, pre-exposure effects, cross-sensitization, and other ideas, involving α-PVP, MDPV, methylone, mephedrone, dibutylone, and other synthetic cathinones.