Pain is a multi-faceted, complex disease that affects all humans. Unfortunately, progress in pain management has been met with limited success. However, considerations of the multiple components of pain have suggested that targeting non-conventional sites could strongly impact the pain management field. The endocannabinoid (eCB) system is one of several lipid signaling systems in the brain and in the body. Verified components of this system include two G-protein coupled receptors, their signaling pathways, two predominant endogenous ligands [anandamide (AEA) and 2-arachidonyl glycerol (2-AG)], and their synthetic and metabolic pathways. The system plays an important modulatory role in many crucial CNS processes (e.g., brain reward, appetite regulation, cognition). Consequently, it is not surprising that this system has been implicated in the pathophysiology of a variety of health problems related to these processes, including pain management. This application is largely based on the idea that a clinically significant component of pain is behavioral depression (i.e., pain-depressed behaviors). In humans, this is indicated by absences from work or school, lack of interest in customary activities, overall decreases in motor activity, and is most often associated with clinical depression. In animals clinical approximation of pain is through decreases in locomotion or grooming and interest in feeding or social interaction. Given these, a promising new strategy for comprehensive treatment of pain is an adjunct focus on pain-depressed behaviors and depressed mood. With this application we plan to evaluate eCB modulation of pain-depressed behaviors using intracranial self-stimulation (ICSS) and drug discrimination (DD) in mice. ICSS has been widely used to study modulation of motivated behavior (i.e. reward) and affect by drugs whereas DD is primarily used to model the subjective/intoxicating effects of drugs. We propose utilizing these well-established operant procedures to evaluate the eCB's effects on pain-induced behavioral depression, affect and intoxication. To complement these behavioral measures, we will determine mechanistic characteristics of affective cannabinoid analgesia versus reward in selected brain regions such as the nucleus accumbens, a brain area implicated in reward and affective pain, through the use of well- established neurochemical analyses such as mass spectrometry and [35S]GTPgS G-protein binding studies. Given the clear need to explore novel therapeutic targets, improve upon existing preclinical pain assays, and incorporate the affective component of pain, we propose that studying the eCB system's modulation of pain-depressed behavior will meet these needs. We feel these studies have significant public health implications and offer a large degree of innovation while relying upon well-established behavioral and neurochemical measures. In summary, considering the paramount public health concern regarding effective pain management this application promises to establish whether the eCB system is a viable and attractive therapeutic means to effectively reduce the great societal burdens associated with pain management.
Pain is a public health concern of utmost importance and is typicaly accompanied by behavioral depression that results in absences from work/school, lack of interest in customary activities, overall decreases in activity, and is most often associated with depresion. Given the clear need to explore novel therapeutic targets, improve upon existing preclinical pain assays, and incorporate the affective component of pain, we propose a thorough evaluation of the endogenous cannabinoid system's ability to ameliorate pain-depressed behavior, while taking into account critical factors relevant to this system such as modulation of reward and intoxication.
|Negus, S Stevens (2018) Addressing the Opioid Crisis: The Importance of Choosing Translational Endpoints in Analgesic Drug Discovery. Trends Pharmacol Sci 39:327-330|
|Negus, S Stevens; Freeman, Kevin B (2018) Abuse Potential of Biased Mu Opioid Receptor Agonists. Trends Pharmacol Sci 39:916-919|
|Owens, Robert A; Mustafa, Mohammed A; Ignatowska-Jankowska, Bogna M et al. (2017) Inhibition of the endocannabinoid-regulating enzyme monoacylglycerol lipase elicits a CB1 receptor-mediated discriminative stimulus in mice. Neuropharmacology 125:80-86|
|Grim, T W; Morales, A J; Thomas, B F et al. (2017) Apparent CB1 Receptor Rimonabant Affinity Estimates: Combination with THC and Synthetic Cannabinoids in the Mouse In Vivo Triad Model. J Pharmacol Exp Ther 362:210-218|
|Bagdas, Deniz; Muldoon, Pretal P; AlSharari, Shakir et al. (2016) Expression and pharmacological modulation of visceral pain-induced conditioned place aversion in mice. Neuropharmacology 102:236-43|
|Owens, Robert A; Ignatowska-Jankowska, Bogna; Mustafa, Mohammed et al. (2016) Discriminative Stimulus Properties of the Endocannabinoid Catabolic Enzyme Inhibitor SA-57 in Mice. J Pharmacol Exp Ther 358:306-14|
|Alajaji, Mai; Lazenka, Matthew F; Kota, Dena et al. (2016) Early adolescent nicotine exposure affects later-life cocaine reward in mice. Neuropharmacology 105:308-317|
|Grim, T W; Morales, A J; Gonek, M M et al. (2016) Stratification of Cannabinoid 1 Receptor (CB1R) Agonist Efficacy: Manipulation of CB1R Density through Use of Transgenic Mice Reveals Congruence between In Vivo and In Vitro Assays. J Pharmacol Exp Ther 359:329-339|
|Leitl, Michael D; Negus, S Stevens (2016) Pharmacological modulation of neuropathic pain-related depression of behavior: effects of morphine, ketoprofen, bupropion and [INCREMENT]9-tetrahydrocannabinol on formalin-induced depression of intracranial self-stimulation in rats. Behav Pharmacol 27:364-76|
|Negus, S Stevens; Neddenriep, Bradley; Altarifi, Ahmad A et al. (2015) Effects of ketoprofen, morphine, and kappa opioids on pain-related depression of nesting in mice. Pain 156:1153-60|
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