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Ronald B. Tjalkens, Ph.D.

Professor and Toxicology Section Head

Office: 121 Physiology
Office Phone: 970-491-2825


Dr. Tjalkens' PubMed Publications


Research projects focus on neuroinflammatory mechanisms in neurodegenerative disorders, particularly disorders of the basal ganglia such as manganism and Parkinson’s disease. Specific areas of interest include inflammatory activation of microglia and astrocytes, astrocyte biology and calcium signaling, mitochondrial dysfunction, and molecular regulation of neuro-inflammatory genes. Approaches emphasize multi-dimensional fluorescence imaging, transgenic models, and molecular approaches to modulate gene expression in neural cells.


Ph.D.: Toxicology, The University of Colorado School of Pharmacy & Pharmaceutical Sciences, Aurora, CO: 1993

B.S.: Toxicology/Biochemistry, The University of California, San Diego, CA: 1992

Selected Publications

Streifel KM, Gonzales A, Trout B, Mohl B, Earley S, and Tjalkens RB. Dopaminergic neurotoxicants cause biphasic inhibition of purinergic calcium signaling in astrocytes, (in press, PLoS One)

Kirkley KS, Madl JE, Duncan C, Gulland FM and Tjalkens RB, Domoic acid-induced seizures in California sea lions (Zalophus californianus) are associated with neuroinflammatory brain injury. DOI: 10.1016/j.aquatox.2014.09.003 [in press, Epub ahead of print, 16 Sep 2014]

Miller JA, Kirkley KA, Padmanabhan R, Liang LP, Raol YH, Patel M, Bialecki RA, Tjalkens RB. Repeated exposure to low doses of kainic acid activates nuclear factor kappa B (NF-?B) prior to seizure in transgenic NF-?B/EGFP reporter mice. Neurotoxicology, 44C:39-47, 2014. PMID: 24813937

Lee SO, Li X, Hedrick E, Jin UH, Tjalkens RB, Backos DS, Li L, Zhang Y, Wu Q, Safe S. Diindolylmethane Analogs Bind NR4A1 and Are NR4A1 Antagonists in Colon Cancer Cells. Mol Endocrinol. 2014, Aug 6:me20141102. [Epub ahead of print]. PMID: 25099012

Dooley GP, Tjalkens RB, Hanneman WH. The atrazine metabolite diaminochlorotriazine suppresses LH release from murine LßT2 cells by suppressing GnRH-induced intracellular calcium transients. Toxicol. Res., 2(3):180-186, 2013, PMID: 24052811

De Miranda DR, Miller JA, Hansen RJ, Lunghofer PJ, Safe S, Gustafson DL, Colagiovanni D, and Tjalkens RB, Neuroprotective efficacy and pharmacokinetic behavior of novel para-phenyl substituted diindolylmethanes in a mouse model of Parkinson’s disease, Journal of Pharmacology and Experimental Therapeutics 345(1) 125-138, 2013, PMID: 23318470

Streifel KM, Miller JA, Mouneimne R, and Tjalkens RB. Manganese inhibits ATP-induced calcium entry through the transient receptor potential channel TRPC3 in astrocytes, Neurotoxicology (34) 160-166, 2012, PMID: 23131343

Streifel KM, Moreno JA, Legare ME, Hanneman WH, and Tjalkens RB. Gene deletion of nos2 protects against manganese-induced neurological dysfunction in developing mice. Toxicol. Sci. 126(1):183-92, 2012, PMID: 22174044

Polunas M, Halladay A, Tjalkens RB, Philbert MA, Lowndes H, and Reuhl K. Role of oxidative stress and the mitochondrial permeability transition in methylmercury cytotoxicity. Neurotoxicol. 32(5):526-34, 2011, PMID: 21871920

Tjalkens RB, Carbone DL, Wu G. Detection of nitric oxide formation in primary neural cells and tissues. Methods Mol. Biol. 2011;758:267-77. PMID: 21815072

Miller JA, Runkle SA, Tjalkens RB, Philbert MA. 1,3-Dinitrobenzene Induced Metabolic Impairment Through Selective Inactivation of the Pyruvate Dehydrogenase Complex. Toxicol Sci. 2011 May 6. [Epub ahead of print] PMID: 21551353

Moreno JA, Streifel KM, Sullivan KA, Miller JA, and Tjalkens RB. Estrogen suppresses glial activation and protects against manganese neurotoxicity in juvenile transgenic NF-kB reporter mice Toxicol. Sci. 122(1) 121-133, 2011. PMID: 21512103

Miller JA, Trout BR, Sullivan KA, Bialecki RA, Roberts RA, and Tjalkens RB. Low dose MPTP causes inflammatory activation of astrocytes in NF-kappaB reporter mice prior to loss of dopaminergic neurons, J. Neurosci. Res. 89 (3) 406-17, 2011, PMID: 21213241

Roberts RA, Smith RA, Safe S, Szabo C, Tjalkens RB, and Robertson FM. Toxicological and pathophysiological roles of reactive oxygen and nitrogen species. Toxicology. 2010 Oct 9;276(2):85-94. Review. PMID: 20643181

Aschner M, Erikson KM, Hernandez EH, and Tjalkens RB. Manganese and its Role in Parkinson’s Disease: From Transport to Neuropathology. Neuromolecular Med. 2009, 11(4), 252-266, PMID: 19657747

Moreno JA, Yeomans EC, Streifel KM, Sullivan KA, Brattin B, Taylor R, and Tjalkens RB. Age-dependent susceptibility to manganese-induced neurological dysfunction. Toxicol Sci. 2009 Dec;112(2):394-404, PMID: 19812362

Moreno JA, Streifel KM, Sullivan KA, Legare ME, and Tjalkens RB. Developmental exposure to manganese (Mn) increases adult susceptibility to inflammatory activation of glia and neuronal protein nitration. Toxicol Sci. 2009 Dec;112(2):405-15, PMID: 19812365

Carbone DA, Popichak KA, Moreno JA, Safe S, and Tjalkens RB. Suppression of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced nitric oxide synthase 2 expression in astrocytes by a novel diindolyl methane analog protects striatal neurons against apoptosis. Mol. Pharmacol. 75(1):35-43, 2009, PMID: 18840677

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