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Yan X, He W, Pan S. Amphetamine-induced neurite injury in PC12 cells through inhibiting GAP-43 pathway. Neurotoxicology 2022; 93:103-111. [PMID: 36150536 DOI: 10.1016/j.neuro.2022.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 09/17/2022] [Accepted: 09/18/2022] [Indexed: 10/14/2022]
Abstract
Amphetamine (AMPH) causes the degeneration of dopamine terminals in the central nervous system. The mechanisms for this damage are unclear. We found AMPH reduced level of GAP-43 in the striatum of rats that receives rich dopaminergic terminals. Using PC12 cells as dopaminergic neuronal models, we further found that AMPH inhibited GAP-43 and GAP-43 phosphorylation in PC12 cells. The reduced GAP-43 was correlated with neurite injury of PC12 cells. The PKCβ1, an upstream molecule of GAP-43, was also inhibited by AMPH. Phorbol 12-myristate 13-acetate (PMA) as a specific activator of PKC increased levels of PKCβ1 and GAP-43, and efficiently prevented neurite degeneration of PC12 cells induced by AMPH. On the other side, enzastuarin, an inhibitor of PKC, decreased levels of PKCβ1 and GAP-43, and caused neurite injury of PC12 cells. Together, our results suggest that AMPH induces neurite injury in PC12 cells through inhibiting PKCβ1/GAP-43 pathway.
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Affiliation(s)
- Xinyu Yan
- Department of Anatomy, Medical College of Jinan University, Guangzhou, Guangdong Province, China; Department of Ultrasound, Yangxin People's Hospital, Yangxin, Hubei Province, China
| | - Wenji He
- Department of Anatomy, Medical College of Jinan University, Guangzhou, Guangdong Province, China; Department of Anatomy, Gannan Medical University, Ganzhou, Jiangxi Province, China
| | - Sanqiang Pan
- Department of Anatomy, Medical College of Jinan University, Guangzhou, Guangdong Province, China.
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Altshuler RD, Mac RC, Gnegy ME, Jutkiewicz EM. PKC inhibition decreases amphetamine-maintained responding under a progressive-ratio schedule of reinforcement. Exp Clin Psychopharmacol 2021; 29:567-572. [PMID: 32940488 PMCID: PMC8611615 DOI: 10.1037/pha0000425] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Protein kinase C (PKC) is important for the mechanism of action of amphetamine (AMPH). Inhibiting PKC blocks AMPH-stimulated increases in extracellular dopamine levels and AMPH-stimulated locomotor activity. This study examined the effects of PKC inhibition on the reinforcing properties of AMPH. Male Sprague-Dawley rats were trained to respond for infusions of 0.032 mg/kg/infusion AMPH or for sucrose pellets under a progressive-ratio (PR) schedule of reinforcement. Number of infusions earned, breakpoints, and session duration were recorded over consecutive sessions. Once AMPH-maintained responding stabilized, rats were treated with 0, 10, or 30 pmol of enzastaurin, a PKCβ-selective inhibitor, or 6 mg/kg 6c, a brain-permeable PKC inhibitor, 18 hr prior to a self-administration session. Pretreatment with 30 pmol enzastaurin or 6 mg/kg 6c decreased the number of AMPH infusions earned and breakpoints without altering sucrose-maintained behaviors. These data suggest that PKC inhibition decreases motivation for AMPH and, therefore, is worth pursuing as a potential treatment for AMPH-use disorder. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
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Affiliation(s)
| | - Ryan C Mac
- Department of Pharmacology, University of Michigan
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Johnson CR, Kangas BD, Jutkiewicz EM, Winger G, Bergman J, Coop A, Woods JH. Novel Antimuscarinic Antidepressant-like Compounds with Reduced Effects on Cognition. J Pharmacol Exp Ther 2021; 377:336-345. [PMID: 33712507 PMCID: PMC8140394 DOI: 10.1124/jpet.120.000337] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 03/09/2021] [Indexed: 11/22/2022] Open
Abstract
The cholinergic nervous system has been implicated in mood disorders, evident in the fast-onset antidepressant effects of scopolamine, a potent muscarinic antagonist, in clinical studies. One prominent disadvantage of the use of scopolamine in the treatment of depression is its detrimental effects on cognition, especially as such effects might aggravate cognitive deficits that occur with depression itself. Thus, the identification of antimuscarinic drugs that are free of such detrimental effects may provide an important avenue for the development of novel therapeutics for the management of depression. The present data in rats indicate that a historical muscarinic antagonist, L-687,306, and a muscarinic antagonist of our own design, CJ2100, were as or more effective than scopolamine in antagonizing both the bradycardic effects of the muscarinic agonist arecoline in cardiovascular studies and its discriminative stimulus and rate-decreasing effects in behavioral studies. Additionally, both novel muscarinic antagonists were as effective as scopolamine in decreasing immobility in the forced swim test, a preclinical indicator of potential antidepressant activity. However, at equieffective or even larger doses, they were considerably less disruptive than scopolamine in assays of cognition-related behavior. All three drugs displayed high specificity for the mAChRs with few off-target binding sites, and CJ2100 showed modest affinity across the mAChRs when compared with L-687,306 and scopolamine. These data emphasize the dissimilar pharmacological profiles that are evident across antimuscarinic compounds and the potential utility of novel antagonists for the improved treatment of depression. SIGNIFICANCE STATEMENT: Some clinical studies with the muscarinic antagonist scopolamine document its ability to produce antidepressant effects in patients with mood disorders; however, scopolamine also has well known adverse effects on both autonomic and centrally mediated physiological functions that limit its therapeutic use. This study characterizes the cardiovascular and discriminative stimulus effects of two novel muscarinic antagonists, L-687,306 and CJ2100, that produce antidepressant-like effects in a rodent model (forced swim test) without affecting touchscreen-based cognitive performance (titrating psychomotor vigilance and delayed matching-to-position).
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Affiliation(s)
- Chad R Johnson
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland (C.R.J., A.C.); Department of Psychiatry, Harvard Medical School, Boston, Massachusetts (B.D.K., J.B.); Department of Pharmacology, University of Michigan, Ann Arbor, Michigan (E.M.J.); Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas (G.W., J.H.W.)
| | - Brian D Kangas
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland (C.R.J., A.C.); Department of Psychiatry, Harvard Medical School, Boston, Massachusetts (B.D.K., J.B.); Department of Pharmacology, University of Michigan, Ann Arbor, Michigan (E.M.J.); Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas (G.W., J.H.W.)
| | - Emily M Jutkiewicz
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland (C.R.J., A.C.); Department of Psychiatry, Harvard Medical School, Boston, Massachusetts (B.D.K., J.B.); Department of Pharmacology, University of Michigan, Ann Arbor, Michigan (E.M.J.); Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas (G.W., J.H.W.)
| | - Gail Winger
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland (C.R.J., A.C.); Department of Psychiatry, Harvard Medical School, Boston, Massachusetts (B.D.K., J.B.); Department of Pharmacology, University of Michigan, Ann Arbor, Michigan (E.M.J.); Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas (G.W., J.H.W.)
| | - Jack Bergman
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland (C.R.J., A.C.); Department of Psychiatry, Harvard Medical School, Boston, Massachusetts (B.D.K., J.B.); Department of Pharmacology, University of Michigan, Ann Arbor, Michigan (E.M.J.); Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas (G.W., J.H.W.)
| | - Andrew Coop
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland (C.R.J., A.C.); Department of Psychiatry, Harvard Medical School, Boston, Massachusetts (B.D.K., J.B.); Department of Pharmacology, University of Michigan, Ann Arbor, Michigan (E.M.J.); Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas (G.W., J.H.W.)
| | - James H Woods
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland (C.R.J., A.C.); Department of Psychiatry, Harvard Medical School, Boston, Massachusetts (B.D.K., J.B.); Department of Pharmacology, University of Michigan, Ann Arbor, Michigan (E.M.J.); Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas (G.W., J.H.W.)
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