R A Glennon

Virginia Commonwealth University, Richmond, Virginia, United States

Are you R A Glennon?

Claim your profile

Publications (398)1198.85 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Background and PurposeCertain methcathinone (MCAT) analogs are psychostimulants of growing drug-abuse concern. This study extends an initial quantitative structure-activity relationship (QSAR) investigation that demonstrated important steric considerations of seven 4- (or para-)substituted analogs of MCAT. Specifically, the steric character (Taft's steric ES) of the 4-position substituent influenced in vitro potency to promote monoamine release via dopamine and serotonin transporters (DAT and SERT) and in vivo modulation of intracranial self-stimulation (ICSS). Here, we delve farther into this QSAR analysis by examining other steric properties of the 4-position substituents.Experimental ApproachDefinitive steric parameters that more explicitly focus on the volume, width, and length of the MCAT 4-position substituents were examined. In addition, homology models of hDAT and hSERT based on the crystallized Drosophila DAT were constructed and docking studies were performed, followed by HINT analysis of the docking results.Key ResultsThe potency of seven MCAT analogs at DAT was found to be negatively correlated with the volume and maximal width of their 4-position substituents, whereas potency at SERT increased as substituent volume and length increased. SERT/DAT selectivity, as well as abuse-related drug effects in the ICSS procedure, also correlated with the same parameters. Docking solutions offered a means of visualizing these findings.Conclusions and ImplicationsThese results suggest that steric aspects of the 4-position substituents of MCAT analogs are key determinants of their action and selectivity, and that the hydrophobic nature of these substituents is involved in their potency at SERT.
    British Journal of Pharmacology 12/2014; · 5.07 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background and PurposeMethcathinone (MCAT) is a potent monoamine releaser and parent compound to emerging drugs of abuse including mephedrone (4-CH3 MCAT), the para-methyl analog of MCAT. This study examined quantitative structure-activity relationships (QSAR) for MCAT and six para-substituted MCAT analogs on (a) in vitro potency to promote monoamine release via dopamine and serotonin transporters (DAT and SERT), and (b) in vivo modulation of intracranial self-stimulation (ICSS), a behavioral procedure used to evaluate abuse potential. Correlations were evaluated for neurochemical and behavioral effects relative to steric (Es), electronic (σp) and lipophilic (πp) parameters of the para substituents.Experimental ApproachFor neurochemical studies, drug effects on monoamine release through DAT and SERT were evaluated in rat-brain synaptosomes. For behavioral studies, drug effects were tested in male Sprague-Dawley rats implanted with electrodes targeting the medial forebrain bundle and trained to respond on a lever for electrical brain stimulation (2.2–1.75 log Hz).Key ResultsMCAT and all six para-substituted analogs promoted monoamine release via DAT and SERT and produced dose- and time-dependent modulation of ICSS. In vitro DAT-vs.-SERT selectivity correlated with in vivo efficacy to produce abuse-related ICSS facilitation (R=0.92, P=0.003). In addition, the Es values of the para substituents correlated with both DAT-vs.-SERT selectivity (R=0.78, P=0.04) and magnitude of ICSS facilitation (R=0.81, P=0.03).Conclusions and ImplicationsThese results suggest that in vitro DAT-vs.-SERT selectivity is a key determinant of abuse-related ICSS facilitation by these MCAT analogs, and steric aspects of para substituents of the MCAT scaffold (indicated by Es) are key determinants of DAT-vs.-SERT selectivity.
    British Journal of Pharmacology 12/2014; · 5.07 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Neuropeptide S (NPS) is a neurotransmitter that activates the NPS receptor to modulate biological functions including anxiety-like behaviors, feeding, and drug reinforcement. RTI-118 is a novel NPS receptor antagonist that decreased cocaine self-administration in rats at doses that had little or no effect on food-maintained responding. To build on these previous findings, this study examined effects of RTI-118 on cocaine-induced facilitation of intracranial self-stimulation (ICSS) in rats. To provide a context for data interpretation, effects of RTI-118 were compared to effects of the kappa opioid receptor agonist U69,593, because the kappa opioid receptor is another peptide neurotransmitter receptor reported to modulate abuse-related cocaine effects. RTI-118 effects were also examined on ICSS facilitation produced by methylenedioxypyrovalerone (MDPV), a novel designer drug of abuse with some cocaine-like effects. Male Sprague-Dawley rats (n=12) with electrodes targeting the medial forebrain bundle responded under a fixed-ratio 1 schedule for range of brain stimulation frequencies. Under control conditions, brain stimulation maintained a frequency-dependent increase in ICSS rates. Cocaine (1.0-10mg/kg) and MDPV (3.2mg/kg) facilitated ICSS. RTI-118 (3.2-32mg/kg) alone produced little effect on ICSS but dose dependently blocked cocaine-induced ICSS facilitation. U69,593 (0.25-0.5mg/kg) also attenuated cocaine effects, but blockade of cocaine effects was incomplete even at a U69,593 dose that alone depressed ICSS. RTI-118 (32mg/kg) failed to block MDPV-induced ICSS facilitation. These results support further consideration of NPS receptor antagonists as candidate treatments for cocaine abuse and provide evidence for differential effects of a candidate treatment on abuse-related effects of cocaine and MDPV.
    European journal of pharmacology. 09/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Monoamine transporters have been implicated in dopamine or serotonin release in response to abused drugs such as methamphetamine or ecstasy (MDMA). In addition, monoamine transporters show substrate-induced inward currents that may modulate excitability and Ca(2+) mobilization, which could also contribute to neurotransmitter release. How monoamine transporters modulate Ca(2+) permeability is currently unknown. We investigate the functional interaction between the human serotonin transporter (hSERT) and voltage-gated Ca(2+) channels (CaV). We introduce an excitable expression system consisting of cultured muscle cells genetically engineered to express hSERT. Both 5HT and S(+)MDMA depolarize these cells and activate the excitation-contraction (EC)-coupling mechanism. However, hSERT substrates fail to activate EC-coupling in CaV1.1-null muscle cells, thus implicating Ca(2+) channels. CaV1.3 and CaV2.2 channels are natively expressed in neurons. When these channels are co-expressed with hSERT in HEK293T cells, only cells expressing the lower-threshold L-type CaV1.3 channel show Ca(2+) transients evoked by 5HT or S(+)MDMA. In addition, the electrical coupling between hSERT and CaV1.3 takes place at physiological 5HT concentrations. The electrical coupling between monoamine neurotransmitter transporters and Ca(2+) channels such as CaV1.3 is a novel mechanism by which endogenous substrates (neurotransmitters) or exogenous substrates (like ecstasy) could modulate Ca(2+)-driven signals in excitable cells.
    Cell calcium 07/2014; 56(1):25-33. · 4.29 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A fundamental understanding of the interaction of ligands with biological receptors is important since many drugs exert their influence via receptors. Using a cluster approach, we have studied the role of structural and electronic parameters on receptor-ligand binding by carrying out density functional theory based calculations. As model systems, we have studied substituted arylguanidines, which activate 5-HT3 receptors in a manner similar to that of serotonin. The geometries of the aryl guanidine derivatives were fully optimized to obtain the lowest energy structures. Electronic properties such as binding energies, dipole moments, polarizabilities, and electron affinities, as well as geometric properties, such as molecular volume and dihedral angles were calculated, and their relationship with binding affinity was evaluated. Results obtained were compared to experimental ligand-receptor binding affinity data available. These fundamental studies show that while both electronic and geometric properties of the ligands are important for binding, the electron affinities of the substituent species play a dominant role. Potential new fundamental indices for ligand-receptor affinity are also discussed.
    The journal of physical chemistry. A. 05/2014;
  • Louis J De Felice, Richard A Glennon, Sidney S Negus
    [Show abstract] [Hide abstract]
    ABSTRACT: This mini-review summarizes the history of cathinone and its synthesized derivatives from early records to the present day, including the appearance of synthetic cathinones in the drug combination known as bath salts. Bath salts may consist of one compound (MDPV) or combinations of MDPV and one or more other synthetic cathinones, which may also appear alone without MDPV. We briefly review recent in vitro studies of bath salts components alone or in combination, focusing on pharmacological and biophysical studies. Finally we summarize new data from in vivo procedures that characterize the abuse-related neurochemical and behavioral effects of synthetic cathinones in rats.
    Life sciences 11/2013; · 2.56 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Synthetic cathinones, beta-keto analogs of amphetamine (or, more correctly, of phenylalkylamines), represent a new and growing class of abused substances. Several such analogs have been demonstrated to act as dopamine (DA) releasing agents. Methylenedioxypyrovalerone (MDPV) was the first synthetic cathinone shown to act as a cocaine-like DA reuptake inhibitor. MDPV and seven deconstructed analogs were examined to determine which of MDPV's structural features account(s) for uptake inhibition. In voltage-clamped (-60 mV) Xenopus oocytes transfected with the human DA transporter (hDAT), all analogs elicited inhibitor-like behavior shown as hDAT-mediated outward currents. Using hDAT-expressing mammalian cells we determined the affinities of MDPV and its analogs to inhibit uptake of [3H]DA by hDAT that varied over a broad range (IC50 values ca 135 to >25,000 nM). The methylenedioxy group of MDPV made a minimal contribution to affinity, the carbonyl group and a tertiary amine are more important, and the extended beta-alkyl group seems most important. Either a tertiary amine, or the extended beta-alkyl group (but not both), are required for the potent nature of MDPV as an hDAT inhibitor.
    ACS Chemical Neuroscience 10/2013; · 3.87 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Abuse of synthetic cathinones, popularized as "bath salts," has increased dramatically in the USA since their debut in 2010. Preclinical behavioral studies may clarify determinants of the abuse-related effects produced by these compounds. This study examined behavioral effects of (±)-methcathinone, (±)-3,4-methylenedioxypyrovalerone (MDPV), (±)-3,4-methylenedioxymethcathinone (methylone), and (±)-4-methylmethcathinone (mephedrone) in rats using intracranial self-stimulation (ICSS). Male Sprague-Dawley rats (n = 18) with electrodes targeting the medial forebrain bundle responded for multiple frequencies of brain stimulation and were tested in two phases. First, dose-effect curves for methcathinone (0.1-1.0 mg/kg), MDPV (0.32-3.2 mg/kg), methylone (1.0-10 mg/kg), and mephedrone (1.0-10 mg/kg) were determined. Second, time courses were determined for effects produced by the highest dose of each compound. Methcathinone produced dose- and time-dependent facilitation of ICSS. MDPV, methylone, and mephedrone produced dose- and time-dependent increases in low rates of ICSS maintained by low brain stimulation frequencies, but also produced abuse-limiting depression of high ICSS rates maintained by high brain stimulation frequencies. Efficacies to facilitate ICSS were methcathinone ≥ MDPV ≥ methylone > mephedrone. Methcathinone was the most potent compound, and MDPV was the longest acting compound. All compounds facilitated ICSS at some doses and pretreatment times, which is consistent with abuse liability for each of these compounds. However, efficacies of compounds to facilitate ICSS varied, with methcathinone displaying the highest efficacy and mephedrone displaying the lowest efficacy to facilitate ICSS.
    Psychopharmacology 08/2013; · 4.06 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: RATIONALE: Psychoactive "bath salts" represent a relatively new drug of abuse combination that was placed in Schedule I in October 2011. Two common ingredients of bath salts include the cathinone analogs: mephedrone and methylenedioxypyrovalerone (MDPV). The mechanism of action of these synthetic cathinone analogs has not been well investigated. MATERIALS AND METHODS: Because cathinone and methcathinone are known to act as releasing agents at the human dopamine transporter (hDAT), mephedrone and MDPV were investigated at hDAT expressed in Xenopus oocytes. RESULTS: Whereas mephedrone was found to have the signature of a dopamine-releasing agent similar to methamphetamine or methcathinone, MDPV behaved as a cocaine-like reuptake inhibitor of dopamine. CONCLUSIONS: Mephedrone and MDPV produce opposite electrophysiological signatures through hDAT expressed in oocytes. Implications are that the combination (as found in bath salts) might produce effects similar to a combination of methamphetamine and cocaine.
    Psychopharmacology 01/2013; · 4.06 Impact Factor
  • Biophysical Journal 01/2013; 104(2):110-. · 3.67 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND AND PURPOSE: Bath Salts is the street name for drug combinations that contain synthetic cathinone analogues, among them possibly mephedrone (MEPH) and certainly methylenedioxypyrovalerone (MDPV). In animal studies, cathinone and certain cathinone analogues release dopamine (DA), similar to the action of amphetamine and methamphetamine (AMPH, METH). AMPH and METH act on the human dopamine transporter (hDAT); thus, we investigated MEPH and MDPV acting at hDAT. EXPERIMENTAL APPROACH: We recorded electrical currents mediated by hDAT expressed in Xenopus laevis oocytes and exposed to: DA, METH, a known hDAT stimulant and DA releaser, MEPH, MDPV, MEPH + MDPV, or cocaine, a known hDAT inhibitor. KEY RESULTS AND CONCLUSIONS: DA, METH, and MEPH induce an inward current (depolarizing) when the oocyte is held near the resting potential (-60 mV), therefore acting as excitatory hDAT substrates. Structurally analogous MDPV induces an outward (hyperpolarizing) current similar to cocaine, therefore acting as an inhibitory non-substrate blocker. IMPLICATIONS: Two components of bath salts, MEPH and MDPV produce opposite effects at hDAT that are comparable to METH and cocaine, respectively. In our assay MEPH is nearly as potent as METH; however, MDPV is much more potent than cocaine and its effect is longer lasting. When applied in combination, MEPH exhibits faster kinetics than MDPV, viz., the MEPH depolarizing current occurs seconds before the slower MDPV hyperpolarizing current. Bath salts containing MEPH (or a similar drug) and MDPV might then be expected initially to release DA and subsequently prevent its reuptake via hDAT. Such combined action possibly underlies some of the reported effects of bath salts abuse.
    British Journal of Pharmacology 11/2012; · 5.07 Impact Factor
  • Source
    Bioorganic & Medicinal Chemistry Letters. 10/2012; 22(20):6526.
  • Biophysical Journal 01/2012; 102(3):215-. · 3.67 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Desformylflustrabromine (dFBr; 1), perhaps the first selective positive allosteric modulator of α4β2 neuronal nicotinic acetylcholine (nACh) receptors, was deconstructed to determine which structural features contribute to its actions on receptors expressed in Xenopus ooycytes using two-electrode voltage clamp techniques. Although the intact structure of 1 was found to be optimal, several deconstructed analogs retained activity. Neither the 6-bromo substituent nor the entire 2-position chain is required for activity. In particular, reduction of the olefinic side chain of 1, as seen with 6, not only resulted in retention of activity/potency but in enhanced selectivity for α4β2 versus α7 nACh receptors. Pharmacophoric features for the allosteric modulation of α4β2 nACh receptors by 1 were identified.
    Journal of Medicinal Chemistry 09/2011; 54(20):7259-67. · 5.61 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The 5-hydroxytryptamine (5-HT) 1E receptor is highly expressed in the human frontal cortex and hippocampus, and this distribution suggests the function of 5-HT(1E) receptors might be linked to memory. To test this hypothesis, behavioral experiments are needed. Because rats and mice lack a 5-HT(1E) receptor gene, knockout strategies cannot be used to elucidate this receptor's functions. Thus, selective pharmacological tools must be developed. The tryptamine-related agonist BRL54443 [5-hydroxy-3-(1-methylpiperidin-4-yl)-1H-indole] is one of the few agents that binds 5-HT(1E) receptors with high affinity and some selectively; unfortunately, it binds equally well to 5-HT(1F) receptors (K(i) ≈ 1 nM). The differences between tryptamine binding requirements of these two receptor populations have never been extensively explored; this must be done to guide the design of analogs with greater selectivity for 5-HT(1E) receptors versus 5-HT(1F) receptors. Previously, we determined the receptor binding affinities of a large series of tryptamine analogs at the 5-HT(1E) receptor; we now examine the affinities of this same series of compounds at 5-HT(1F) receptors. The affinities of these compounds at 5-HT(1E) and 5-HT(1F) receptors were found to be highly correlated (r = 0.81). All high-affinity compounds were full agonists at both receptor populations. We identified 5-N-butyryloxy-N,N-dimethyltryptamine as a novel 5-HT(1F) receptor agonist with >60-fold selectivity versus 5-HT(1E) receptors. There is significant overlap between 5-HT(1E) and 5-HT(1F) receptor orthosteric binding properties; thus, identification of 5-HT(1E)-selective orthosteric ligands will be difficult. The insights generated from this study will inform future drug development and molecular modeling studies for both 5-HT(1E) and 5-HT(1F) receptors.
    Journal of Pharmacology and Experimental Therapeutics 03/2011; 337(3):860-7. · 3.89 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Serotonin 5-HT(6) receptors have been implicated in the regulation of cognition, locomotion, and mood, but the elucidation of their functions is complicated by conflicting data using various animal models. Here, a systematic evaluation showed that autoradiographic binding with the selective 5-HT(6) receptor antagonist [(125) I]SB-258585 was similar in marmosets and rats. In both species, [(125) I]SB-258585 binding was enriched in the caudate-putamen. Various recently developed agonists and antagonists toward 5-HT(6) receptors exhibited similarities in their abilities to displace [(125) I]SB-258585 binding in marmosets and rats. The rank order of pEC50 values were as follows: (+)EMDT-CR = EMD386088>MS-245 = 5-HT>EMDT>(-)EMDT-CR; and (+)EMDT-CR = EMD386088>5-HT = MS-245 = EMDT>(-)EMDT-CR, in marmosets and rats, respectively. Unilateral 6-hydroxydopamine lesioning of dopaminergic axons caused a significant decrease of [(125) I]SB-258585 binding in the caudate-putamen of both marmosets and rats. Nonetheless, acute administration of the 5-HT(6) receptor agonist EMDT to unilaterally 6-hydroxydopamine-lesioned rats, caused an induction of egr-1, homer, and enkephalin mRNAs in the dopamine-depleted hemisphere, indicating a supersensitization of 5-HT(6) receptors following dopamine depletion. In conclusion, this study provides evidence for significant similarities in the distribution, level, pharmacology, and regulation of 5-HT(6) receptors between rats and marmosets.
    The Journal of Comparative Neurology 02/2011; 519(9):1816-27. · 3.66 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: (-)Nicotine produces antinociceptive effects in rodents. meta-Chlorophenylguanidine (MD-354), an analgesia-enhancing agent, binds at 5-HT(3) and alpha(2)-adrenoceptors and potentiates the antinociceptive effects of an "inactive" dose of clonidine. The present study examined the actions of MD-354 on (-)nicotine-induced antinociception. Mouse tail-flick and other assays were employed. In the tail-flick assay, (-)nicotine (ED(50) = 1.66 mg/kg) but not MD-354 produced dose-related antinociceptive effects. Administered in combination with (-)nicotine (2.5 mg/kg), MD-354 (AD(50) = 3.4 mg/kg) did not potentiate, but effectively antagonized the antinociceptive actions of (-)nicotine. In a mouse hot-plate assay, MD-354 failed to modify (-)nicotine responses. In combination with a locomotor activity-suppressing dose of (-)nicotine, MD-354 (up to 17 mg/kg) failed to antagonize (-)nicotine-induced hypolocomotion. In a rat drug discrimination paradigm using (-)nicotine as training drug, MD-354 produced saline-appropriate responding; in combination with the training dose of (-)nicotine, MD-354 failed to antagonize the nicotine cue. MD-354 selectively antagonizes the antinociceptive actions of (-)nicotine in the tail-flick, but not in the hot-plate assay, or either the motor effects, or discriminative stimulus effects of (-)nicotine. The most parsimonious explanation is that MD-354 might act as a negative allosteric modulator of alpha 7 nACh receptors, and radioligand binding and functional data are provided to support this conclusion.
    Psychopharmacology 07/2010; 210(4):547-57. · 4.06 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 06/2010; 31(23).
  • [Show abstract] [Hide abstract]
    ABSTRACT: Arylsulfonyl analogs of aminopyrimidines (e.g. Ro 04-6790; 2), aminopyridines (e.g. Ro 63-0563; 3), 1-phenylpiperazines (e.g. SB-271046; 4), and tryptamines (e.g. MS-245; 5) were described as the first examples of selective 5-HT(6) receptor antagonists only ten years ago. Today, hundreds of compounds of seemingly diverse structure have been reported. The early antagonists featured an arylsulfonyl group leading to the wide notspread assumption that an arylsulfonyl moiety might be critical for binding and antagonist action. With respect to the arylsulfonyltryptamines, it seems that neither the "arylsulfonyl" nor the "tryptamine" portion of these compounds is essential for binding or for antagonist action, and some such derivatives even display agonist action. The present review describes many of the currently available 5-HT(6) receptor ligands and, unlike prior reviews, provides a narrative of the thinking (where possible) that led to their design, synthesis, and evaluation. The arylsulfonyltryptamines are also used as the structural basis of attempts to relate various structure-types to one another to afford a better understanding of the overall structural requirements for 5-HT(6) receptor binding.
    Current topics in medicinal chemistry 02/2010; 10(5):579-95. · 4.47 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Sigma-2 (sigma(2)) binding sites are an emerging target for anti-neoplastic agents due to the strong apoptotic effect exhibited by sigma(2) agonists in vitro and the overexpression of these sites in tumor cells. Nonetheless, no sigma(2) receptor protein has been identified. Affinity chromatography using the high-affinity sigma(2) ligand PB28 and human SK-N-SH neuroblastoma cells was previously utilized to identify sigma(2) ligand binding proteins, specifically histones H1, H2A, H2B, and H3.3a. To rationalize this finding, homology modeling and automated docking studies were employed to probe intermolecular interactions between PB28 and human nucleosomal proteins. These studies predicted interaction of PB28 with the H2A/H2B dimer at a series of sites previously found to be implicated in chromatin compaction and nucleosomal assembly. To experimentally verify this prediction, a competitive binding assay was performed on the reconstituted H2A/H2B dimer using [(3)H]PB28 as radioligand, and an IC(50) value of 0.50 nM was determined for PB28 binding. In addition, [(3)H]PB28 was found to accumulate with up to a fivefold excess in nuclear fractions over cytosolic fractions of SK-N-SH and MCF7 cells, indicating that PB28 is capable of entering the nucleus to interact with histone proteins. In conjunction with computational results, these data suggest that PB28 may exert its cytotoxic effect through direct interaction with nuclear material.
    ChemMedChem 02/2010; 5(2):268-73. · 2.84 Impact Factor

Publication Stats

6k Citations
1,198.85 Total Impact Points

Institutions

  • 1978–2014
    • Virginia Commonwealth University
      • • Department of Medicinal Chemistry
      • • Department of Physiology and Biophysics
      • • School of Pharmacy
      Richmond, Virginia, United States
  • 1983–2013
    • Julphar School of Pharmacy
      United States
  • 2009–2010
    • Università degli Studi di Bari Aldo Moro
      • Sezione di Urologia e Andrologia
      Bari, Apulia, Italy
    • University of California, San Francisco
      • Department of Pharmaceutical Chemistry
      San Francisco, CA, United States
  • 2003–2010
    • University of Richmond
      Richmond, Virginia, United States
  • 2000–2010
    • University of Camerino
      • Dipartimento di Scienze Chimiche
      Matelica, The Marches, Italy
  • 2003–2005
    • Case Western Reserve University
      • Department of Biochemistry
      Cleveland, OH, United States
  • 1990–2003
    • National Institute on Drug Abuse
      Maryland, United States
  • 2000–2002
    • Florida A&M University
      • College of Pharmacy and Pharmaceutical Sciences
      Tallahassee, FL, United States
  • 1992
    • Richmond VA Medical Center
      Richmond, Virginia, United States
  • 1985–1990
    • Albany Medical College
      • Center for Neuropharmacology and Neuroscience
      Albany, New York, United States
  • 1989
    • Johns Hopkins University
      • Department of Neuroscience
      Baltimore, MD, United States
  • 1986
    • Hackensack University Medical Center
      Hackensack, New Jersey, United States
  • 1984–1985
    • Northeast Ohio Medical University
      Ravenna, Ohio, United States