Laboratory of Behavioral and Cell-Based Pharmacognosy

Laboratory of

Behavioral & Cell-Based Pharmacognosy

Lance McMahon works at the bench

Directors

Takato Hiranita

Takato Hiranita Ph.D.

Research Assistant Professor
Department: Pharmacodynamics
Phone: (352) 294-5411
Jenny Wilkerson

Jenny Wilkerson Ph.D.

Research Assistant Professor
Department: Pharmacodynamics
Phone: (352) 294-8908

Postdoctoral Associates

Samuel Obeng

Samuel Obeng Ph.D.

Assistant Scientist
Department: Pharmacodynamics

 

Laboratory of Behavioral and Cell-Based Pharmacognosy

Research Assistants

  • Jasmine Felix, B.S.
  • Anna Pennington, B.S.
  • Morgan Reeves, B.S.
  • Luis Restrepo, B.S.

Biological Scientists

  • Victoria Taylor, M.S.

Undergraduate Fellows

  • Avi Patel
  • Paula Paseiro
 


Research Projects

Kratom (Mitragyna speciosa) is a Thai medicinal herb used as a self-treatment for opioid use disorder.

Kratom (Mitragyna speciosa)

Kratom is a Thai medicinal herb used as a self-treatment for opioid use disorder. Mitragynine, the plant’s most abundant alkaloid, is a low efficacy µ receptor agonist with G- protein signaling bias. In close collaboration with the laboratory of Christopher McCurdy, Ph.D., FAAPS, in the Department of Medicinal Chemistry and the Translational Drug Development Core, we are showing that mitragynine has limited abuse-related effects in our preclinical screens. We are showing that mitragynine interacts with non-opioid CNS targets including adrenergic receptors. This project includes a collaborative, interdisciplinary team, that is studying the pharmacophoric elements of mitragynine through synthetic derivatives in an approach that led to the understanding of the essential pharmacophore of morphine. We are using a combination of chemical and prodrug synthesis, in vitro metabolic stability, affinity and efficacy analysis, behavioral assays predictive of receptor mechanism (drug discrimination), abuse (self-administration), and untoward effects (respiratory depression, tolerance, and dependence), and in vivo ADME assays. We are studying all alkaloid constituents in Mitragyna speciosa. We are also creating mitragynine analogs with innovative pharmacological mechanisms that include both opioid and adrenergic activity. Our efforts to identify the pharmacophoric requirements of mitragynine will lead to templates for the design of novel opioid receptor ligands; this will greatly improve the knowledge of interactions of these structurally novel compounds with opioid receptors and facilitate the development of these ligands as treatments for opioid use disorders.

Supported by USPHS grants DA47855 and DA48353


Tobacco dependence in the form of cigarette smoking is a leading cause of cancer as well as cardiovascular and respiratory disease and is the leading preventable cause of death in the United States.

Tobacco dependence

Tobacco dependence in the form of cigarette smoking is a leading cause of cancer as well as cardiovascular and respiratory disease and is the leading preventable cause of death in the United States. Many factors contribute to cigarette smoking, including nicotine, other chemicals in tobacco smoke, and conditioned reinforcers. This project focuses on nicotinic acetylcholine receptors (nAChR) as critical targets for the development of smoking cessation pharmacotherapies. Drug discrimination assays are being used to examine the impact of drug history (nicotine treatment) on the effects of low and high efficacy nAChR agonists and allosteric nAChR modulators. We have shown that the nAChR agonist varenicline (Chantix) becomes less able to mimic the effects of nicotine as animals receive greater amounts of daily nicotine treatment. Currently, we are examining nAChR efficacy (intrinsic activity) as a critical determinant of how well nAChR agonists can mimic the effects of nicotine. Novel nAChR agonists with higher efficacy than varenicline are  being examined for their ability to mimic the effects of nicotine during chronic treatment, whereas novel nAChR agonists with lower efficacy than varenicline will be examined for their ability to antagonize the effects of nicotine during chronic nicotine treatment. We are also comparing the effects of orthosteric and allosteric ligands at nAChRs and, in particular, are examining the potential of allosteric nAChR modulators to modify the effects of nicotine. Both positive and negative allosteric nAChR modulators with selectivity for subtypes of nAChR are being tested under acute and chronic nicotine treatment conditions. We hope to identify pharmacologic dimensions and novel directions upon which to develop novel medications that could further reduce the devastating consequences of cigarette smoking.

Supported by USPHS grant DA2567

Nicotine Publications

Cunningham CS, Moerke MJ, McMahon LR(2019) Discriminative stimulus effects of mecamylamine and nicotine in rhesus monkeys: Central and peripheral mechanisms. Pharmacol Biochem Behav 179:27-33 PMID: 30738085

Moerke MJ, McMahon LR(2019) Nicotine-like discriminative stimulus effects of acetylcholinesterase inhibitors and a muscarinic receptor agonist in rhesus monkeys. Drug Dev Ind Pharm in press PMID: 30712397

McMahon LR(2019) Green tobacco sickness: mecamylamine, varenicline, and nicotine vaccine as clinical research tools and potential therapeutics. Expert Rev Clin Pharmacol 12(3):189-195 PMID: 30650314

de Moura FB, McMahon LR(2018) Differential cross-tolerance to the effects of nicotinic acetylcholine receptor drugs in C57BL/6J mice following chronic varenicline. Behav Pharmacol in press PMID: 30398980

Moerke MJ, McMahon LR(2018) Rapid nicotine tolerance and cross-tolerance to varenicline in rhesus monkeys: Drug discrimination. Exp Clin Psychopharmacol 26:541-548 PMID: 30102063

de Moura FB, McMahon LR(2017) The contribution of α4β2 and non-α4β2 nicotinic acetylcholine receptors to the discriminative stimulus effects of nicotine and varenicline in mice. Psychopharmacology (Berl) 234(5):781-792 PMID: 28028600

Moerke MJ, Zhu AZ, Tyndale RF, Javors MA, McMahon LR(2017) The discriminative stimulus effects of i.v. nicotine in rhesus monkeys: Pharmacokinetics and apparent pA2 analysis with dihydro-β-erythroidine. Neuropharmacology 116:9-17 PMID: 27940077

Cunningham CS, Moerke MJ, Javors MA, Carroll FI, McMahon LR(2016) Attenuated nicotine-like effects of varenicline but not other nicotinic ACh receptor agonists in monkeys receiving nicotine daily. Br J Pharmacol 173(24):3454-3466 PMID: 27667659

Moerke MJ, de Moura FB, Koek W, McMahon LR(2016) Effects of nicotine in combination with drugs described as positive allosteric nicotinic acetylcholine receptor modulators in vitro: discriminative stimulus and hypothermic effects in mice. Eur J Pharmacol 786:169-178 PMID: 27238974

de Moura FB, McMahon LR(2016) Differential antagonism and tolerance/cross-tolerance among nicotinic acetylcholine receptor agonists: scheduled-controlled responding and hypothermia in C57BL/6J mice. Behav Pharmacol 27(2-3 Spec Issue):240-8. PMID: 26910582

Cunningham CS, Moerke MJ, McMahon LR(2014) The discriminative stimulus effects of mecamylamine in nicotine-treated and untreated rhesus monkeys. Behav Pharmacol 25(4):296-305 PMID: 24978703

Rodriguez JS, Cunningham CS, Moura FB, Ondachi P, Carroll FI, McMahon LR(2014) Discriminative stimulus and hypothermic effects of some derivatives of the nAChR agonist epibatidine in mice. Psychopharmacology 231(23):4455-66 PMID: 24800895

Cunningham CS, McMahon LR(2013) Multiple nicotine training doses in mice as a basis for differentiating the effects of smoking cessation aids. Psychopharmacology (Berl) 228(2):321-333 PMID: 23494230

Cunningham CS, Javors MA, McMahon LR(2012) Pharmacologic characterization of a nicotine-discriminative stimulus in rhesus monkeys. J Pharmacol Exp Ther 341(3):840-849 PMID: 22438471

Cunningham CS, McMahon LR(2011) The effects of nicotine, varenicline, and cytisine on schedule-controlled responding in mice: differences in [alpha]4[beta]2 nicotinic receptor activation Eur J Pharmacol 654(1):47-52 PMID: 21172344


(−)-Trans-Δ9-tetrahydrocannabinol (THC)-based analog development

(−)-Trans-Δ9-tetrahydrocannabinol (THC)-based analog development

The current opioid crisis has fueled renewed focus on non-opioid analgesics, including cannabinoid receptor ligands. THC-based analog development has been dominated by one general method, the “biomimetic route,” where a cyclic monoterpene derivative and a phenolic component serve as starting materials. Though effective for certain core substitution patterns, other patterns are inaccessible with this established method, thereby limiting insights into structure-activity relationships and clinical development of cannabinoid receptor ligands. We are optimizing novel protocols to modularly assemble cannabinoids with previously inaccessible substitution patterns, and will prepare first-generation libraries of cannabinoid analogs based on each synthetic protocol. We are developing a convergent and divergent synthetic route to cannabinoid analogs from abundant propargyl chloride, salicylaldehyde, and allyl nitrile starting materials. The route is yielding diverse analogs with unexplored substitution patterns as well as axially chiral cannabinol (CBN)-analogs. We are also devising a protocol for preparing cannabinol benzochromene analogs by hexadehydro-Diels-Alder (HHDA) cycloaddition. We are establishing the in vitrocannabinoid receptor binding affinity of “first generation” THC analogs and examining THC analogs in pre-clinical models of antinociceptive effects, as well as in a well-validated model of CB1receptor-mediated subjective effects. We are establishing the in vitrocannabinoid binding affinity of novel chemical entities in cultured HEK293 cells expressing either human CB1or CB2receptor subtypes. We are identifying the capacity of chemical entities to produce hypothermia and antinociceptive effects, two well-known effects of CB1receptor agonists, in C57BL/6J mice. In a pre-clinical model of subjective effects, i.e., C57BL/6J mice discriminating 5.6 mg/kg THC i.p., we are screening for CB1receptor agonist activity. CB1receptor agonism is further evaluated with the CB1receptor-selective antagonist rimonabant, and CB2receptor agonism is evaluated with the CB2receptor-selective antagonist SR 144528. We expect our novel synthetic approaches for creating new cannabinoid-based drugs to unlock new directions for therapeutic development.

Cannabinoid Publications

Wilkerson JL, Schulze DR, McMahon LR (2019) Tolerance and dependence to Δ⁹-tetrahydrocannabinol in rhesus monkeys: activity assessments. PLoS One 14(3):e0209947 PMID: 30861005

Hruba L, McMahon LR(2017) Apparent affinity estimates and reversal of the effects of synthetic cannabinoids AM-2201, CP-47,497, JWH-122, and JWH-250 by rimonabant in rhesus monkeys. J Pharmacol Exp Ther 362(2):278-286 PMID: 28533288

McMahon LR(2016) Enhanced discriminative stimulus effects of Δ9-THC in the presence of cannabidiol and 8-OH-DPAT in rhesus monkeys. Drug Alcohol Depend  165:87-93 PMID: 27289270

Ghosh S, Kinsey SG, Liu Q, Hruba L, McMahon LR, Wise LE, Abdulla RA, Selley DE, Sim-Selley L, Cravatt BF, Lichtman AH (2015) Full FAAH inhibition combined with partial monoacylglycerol lipase inhibition: Augmented and sustained antinociceptive effects with negligible cannabimimetic side effects in mice. J Pharmacol Exp Ther  354(2):111-120 PMID: 25998048

Hruba L, Seillier A, Zaki A, Cravatt BF, Lichtman AH, Giuffrida A, McMahon LR(2015) Simultaneous inhibition of fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL) shares discriminative stimulus effects with ∆9-THC in mice. J Pharmacol Exp Ther  353(2):261-268 PMID: 25711338

Rodriguez JS, McMahon LR(2014) JWH-018 in rhesus monkeys: differential antagonism of discriminative stimulus, rate-decreasing, and hypothermic effects. Eur J Pharmacol 740:151-159 PMID: 24972243

Rodriguez JS, Cunningham CS, Moura FB, Ondachi P, Carroll FI, McMahon LR(2014) Discriminative stimulus and hypothermic effects of some derivatives of the nAChR agonist epibatidine in mice. Psychopharmacology (Berl) 231(23):4455-4466 PMID: 24800895

Ginsburg BC, Hruba L, Zaki A, Javors MA, McMahon LR(2014) Blood levels do not predict behavioral or physiological effects of Δ⁹-tetrahydrocannabinol in rhesus monkeys with different patterns of exposure. Drug Alcohol Depend 139:1-8 PMID: 24703610

Hruba L, McMahon LR(2014) The cannabinoid agonist HU-210: pseudo-irreversible discriminative stimulus effects in rhesus monkeys. Eur J Pharmacol 727:35-42 PMID: 24486701

Hruba L, Ginsburg BC, McMahon LR(2012) Apparent inverse relationship between cannabinoid agonist efficacy and tolerance/cross-tolerance produced by Δ⁹-tetrahydrocannabinol treatment in rhesus monkeys. J Pharmacol Exp Ther 342(3):843-849 PMID: 22718500

Schulze DR, Carroll FI, McMahon LR(2012) Interactions between dopamine transporter and cannabinoid receptor ligands in rhesus monkeys. Psychopharmacology (Berl) 222(3):425-438 PMID: 22374253

Ginsburg BC, McMahon LR, Sanchez JJ, Javors MA (2012) Purity of synthetic cannabinoids sold online for recreational use. J Anal Toxicol 36(1):66-68 PMID: 22290755

Ginsburg BC, Schulze DR, Hruba L, McMahon LR(2012) JWH-018 and JWH-073: Δ9-tetrahydrocannabinol-like discriminative stimulus effects in monkeys. J Pharmacol Exp Ther 340(1):37-45 PMID: 21965552

Stewart JL, McMahon LR(2011) The fatty acid amide hydrolase inhibitor URB 597: interactions with anandamide in rhesus monkeys. Br J Pharmacol 164(2b):655-666 PMID: 21449917

Singh H, Schulze D, McMahon LR(2011) Tolerance and cross-tolerance to cannabinoids in mice: schedule-controlled responding and hypothermia. Psychopharmacology (Berl) 215(4):665-675 PMID: 21246187

McMahon LR(2011) Chronic Δ9-tetrahydrocannabinol treatment in rhesus monkeys: differential tolerance and cross-tolerance among cannabinoids. Br J Pharmacol 162(5):1060-1073 PMID: 21091643

Javors MA, Sanchez JJ, McMahon LR(2010) Quantification of rimonabant (SR 141716A) in monkey plasma using HPLC with UV detection. J Chromatogr Sci 48(6):491-495 PMID: 20822666

Stewart JL, McMahon LR(2010) Rimonabant-induced Δ9-tetrahydrocannabinol withdrawal in rhesus monkeys: discriminative stimulus effects and other withdrawal signs. J Pharmacol Exp Ther 334(1):347-356 PMID: 20375197

Giuffrida A, McMahon L(2010) In vivo pharmacology of endocannabinoids and their metabolic inhibitors: therapeutic implications in Parkinson‘s disease and abuse liability. Prostaglandins Other Lipid Mediat 91(3-4):90-103 PMID: 19523530

Beardsley PM, Thomas BF, McMahon LR(2009) Cannabinoid CB1 receptor antagonists as potential pharmacotherapies for drug abuse disorders. Int Rev Psychiatry 21(2):134-142 PMID: 19367507

McMahon LR(2009) Apparent affinity estimates of rimonabant in combination with anandamide and chemical analogs of anandamide in rhesus monkeys discriminating Δ9-tetrahydrocannabinol. Psychopharmacology (Berl) 203(2):219-228 PMID: 18592221

McMahon LR, Ginsburg BC, Lamb RJ (2008) Cannabinoid agonists differentially substitute for the discriminative stimulus effects of Delta(9)-tetrahydrocannabinol in C57BL/6J mice. Psychopharmacology (Berl) 198(4):487-495 PMID: 17673980

McMahon LR, Koek W (2007) Differences in the relative potency of SR 141716A and AM 251 as antagonists of various in vivo effects of cannabinoid agonists in C57BL/6J mice. Eur J Pharmacol 569(1-2):70-76 PMID: 17553486

McMahon LR(2006) Discriminative stimulus effects of the cannabinoid CB(1) antagonist SR 141716A in rhesus monkeys pretreated with Δ9-tetrahydrocannabinol. Psychopharmacology (Berl) 188(3):306-314 PMID: 16953389

McMahon LR(2006) Characterization of cannabinoid agonists and apparent pA2 analysis of cannabinoid antagonists in rhesus monkeys discriminating Δ9-tetrahydrocannabinol. J Pharmacol Exp Ther 319(3):1211-1218 PMID: 16943255


Equipment

Behavior

  • 46 rat operant conditioning chambers, each equipped with retractable levers, lights, and pellet delivery dispenser (30 for drug discrimination and simple, schedule-controlled responding and 16 for self-administration)
  • 16 programmable infusion pumps controlling variable Infusion rates (PHM-111-EC, Med Associates)
  • 7 Med-Associates interfaces (one per 8-16 operant conditioning chambers)
  • 7 personal computers with Med-PC software
  • 8 rotarod locomotor activity system (San Diego Instruments)
  • 12 rat whole body plethysmographs (Data Sciences International)
  • 20 automated mouse conditioned place preference units (12 San Diego Instruments and 8 Med Associates)
  • 32 mouse operant conditioning chambers with nose pokes and pellet dispensers (24 for drug discrimination and simple, schedule-controlled responding and 8 for self-administration)
  • 8 mouse locomotor activity chambers
  • 3 hot plates (Columbus Instruments)
  • 4 electronic balances for weighing rodents
  • 7 hot water baths that can be maintained continuously at specified temperature (VWR)
  • 4 Hargreaves Paw flick test apparatuses (IITC Life Sciences)
  • Semmes-Weinstein monofilaments (Stoelting), with wire-mesh von Frey testing platform
  • Noldus EthoVision XT 6.0 video tracking system (Noldus Information Technology)
  • WV-BP330 CCTV camera (Panasonic) available for use in collecting locomotor activity data
  • IBM-PC compatible computers linked to all equipment for automated collection and preliminary analysis of data
  • high security safe
  • 2 microbalances (Mettler Toledo) for weighing drugs
  • vortex
  • 2 sonicators
  • 2 -70ºC freezers

In vitro Receptor Binding

    • plate reader (PerkinElmer 2450-0020)
    • unifilter-96 cell harvester (PerkinElmer C961962)
    • UV absorbance spectrophotometer   (Fisher Scientific 14-377-580)
    • homogenizer/model 120 sonic dismembrator (Fisher Scientific FB120110)
    • precision balances (PL602E Mettler Toledo)
    • benchtop centrifuge (Fisher Scientific 75210062)
    • Ultra centrifuge
    • -20 freezer (Thermo Scientific) TValue Lab Upright Freezers (20LFEETSA)
    • vortex
    • incubator (Thermo Scientific 3141)
    • compound microscopes (Jenco JC series)
    • hemacytometer (Fisher Scientific 02-671-51B)

Weighing powders