Biological Sciences

Ken Rodnick, Ph.D.

Ken Rodnick

Professor of Physiology

Education

Biographical Sketch

I consider myself a comparative physiologist with primary interests in biochemical, cellular and structural adaptations of cardiac and skeletal muscle. Perhaps the most adaptable cells of vertebrates are those that produce or are subjected to mechanical stress, namely myocytes. Muscle is often called a "plastic tissue" because of its extreme adaptability to altered functional demand. Importantly, both cardiac and skeletal muscle are determinants of locomotion and therefore vital tissues for overall animal health and fitness.

My research focuses on understanding how the environmental variables such as temperature, dissolved oxygen, and diet affect physiological performance of fishes. All but a few fishes are in thermal equilibrium with their environment and either cold or warm temperatures present a significant challenge to normal function. Our primary focus is the cardiovascular system of salmonid fishes, with extensions to skeletal muscle. Similar to humans, trout and their hearts are intolerant of hypoxic conditions. We conduct research to identify the metabolic and functional limitations for trout cardiomyocytes during hypoxia and reoxygenation. We are also very interested in understanding sex differences and steroid hormone effects on cardiac energetics and performance. The finding that adult trout and salmon experience coronary arteriosclerosis and potentially cardiac pathology extends this work to biomedical audiences. Ultimately, our work is also directed at helping the aquaculture industry understand nutrient utilization in trout and design better diets to promote efficient growth and health.

My group conducts studies in the field, at aquaculture facilities, and in the laboratory. We employ a variety of techniques, spanning from the molecular to studies of whole animals. Examples of these techniques include field respirometry and swim performance measurements on wild fish, non invasive ECG and echocardiography, direct measurements of blood pressure and cardiac output, in vitro studies with isolated cardiac tissues, biochemical assays of enzyme activity and kinetics, immunoblotting for specific proteins that impact cardiac energetics and calcium balance, and quantitative microscopy.

Teaching

Harmon KJ, Bolinger MT, Rodnick KJ. Carbohydrate energy reserves and effects of food deprivation in male and female rainbow trout. Comp Biochem Physiol A 158:423-431, 2011.

Gamperl AK, Swafford B, Rodnick KJ. Elevated temperature, per se, does not limit the ability of rainbow trout to increase stroke volume. J Therm Biol 36:7-14, 2011.

Marcum R, St-Hilaire S, Murphy PJ, Rodnick KJ. Effects ofBatrachochytrium dendrobatidis on ion concentrations in the boreal toad, Anaxyrus (Bufo) boreas boreas. Dis Aquat Org 91:17-21, 2010.

Chapalamadugu KC, Robison BD, Drew RE, Powell MS, Hill RA, Amberg JJ, Rodnick KJ, Hardy RW, Hill ML, Murdoch, GK. Dietary carbohydrate level affects transcription factor expression that regulates skeletal muscle myogenesis in rainbow trout. Comp Biochem Physiology B 153:66-72, 2009.

Boudina S, Bugger H, Sena m S, O'Neill BT, Zaha VG, Olesya Ilkun JJ, Wright PK, Mazumder E, Palfreyman TJ, Theobald H, Khalimonchuk O, Wayment B, Sheng X, Rodnick KJ, Centini R, Chen D, Litwin SE, Weimer BE, Abel ED. Contribution of impaired myocardial insulin signaling to mitochondrial dysfunction and oxidative stress in the heart. Circulation 119:1272-1283, 2009.

Rodnick KJ, St.-Hilaire S, Battiprolu PK, Seiler SM, Kent ML, Powell MS, Ebersole JL. Habitat selection influences sex distribution, morphology, tissue biochemistry, and parasite load of juvenile coho salmon in the West Fork Smith River, Oregon. Trans Am Fish Soc 137(6):1571-1590, 2008.

Drew RE, Rodnick KJ, Settles ML, Wacyk J, Churchill EJ, Powell MS, Hardy RW, Murdoch GK, Hill RA, Robison BD. Effect of starvation on the transcriptomes of the brain and liver in adult female zebrafish (Danio rerio). Physiol Genomics 35:283-295, 2008.

Cotter PA, Han AJ, Everson JJ, Rodnick KJ. Cardiac hemodynamics of the rainbow trout (Oncorhynchus mykiss) using simultaneous Doppler echocardiography and electrocardiography. J Exp Zool (Part A Ecological Genetics and Physiology) 309:243-254, 2008.

Robison BD, Drew RE, Murdoch GK, Powell M, Rodnick KJ, Settles M, Stone D, Churchill E, Hill RA, Papasani MR, Lewis SS, Hardy RW. Sexual dimorphism in hepatic gene expression and the response to dietary carbohydrate manipulation in the zebrafish (Danio rerio). Comp Biochem Physiol (Part D Genomics and Proteomics) 3:141-154, 2008.

Battiprolu PK, Harmon KJ, Rodnick KJ. Sex differences in energy metabolism and performance of teleost cardiac tissue. Am J Physiol (Regul Integr Comp Physiol) 292:R827-836. 2007.

Cotter PA, Rodnick KJ. Differential effects of anesthetics on electrical properties of the rainbow trout (Oncorhynchus mykiss) heart. Comp Biochem Physiol A (Mol Integr Physiol) 145:158-165, 2006.

Farrar RS, Battiprolu PK, Pierson NS, Rodnick KJ. Steroid-induced cardiac contractility requires exogenous glucose, glycolysis and the sarcoplasmic reticulum in rainbow trout. J Exp Biol 209:2114-2128, 2006.

Alkanani T, Parrish CC, Rodnick KJ, Gamperl AK. Lipid class and nonesterified fatty acid profiles in plasma of North Atlantic cod (Gadus morhua) from Newfoundland. Can J Fish Aquat Sci 52:2509-2518, 2005.

Clark JJ, Clark RJ, McMinn JT, Rodnick KJ. Microvascular and biochemical compensation during ventricular hypertrophy in male rainbow trout. Comp Biochem Physiol B 139:695-703, 2004.

Gamperl AK, Faust HA, Dougher B, Rodnick KJ. Hypoxia tolerance and preconditioning are not additive in the trout (Oncorhynchus mykiss) heart. J Exp Biol 207:2497-2505, 2004.

Farrar RS, Rodnick KJ. Sex-dependent effects of gonadal steroids and cortisol on cardiac contractility in rainbow trout. J Exp Biol 207:2083-2093, 2004.

Clow KA, Rodnick KJ, MacCormack TJ, Driedzic WR. The regulation and importance of glucose uptake in the isolated Atlantic cod heart: rate-limiting steps and effects of hypoxia. J Exp Biol 207:1865-1874., 2004.

Faust HA, Gamperl, AK, Rodnick KJ. All rainbow trout (Oncorhynchus mykiss) are not created equal: intra-specific variation in cardiac hypoxia tolerance. J Exp Biol 207:1005-1015, 2004.

Rodnick KJ, Gamperl AK, Lizars KR, Bennett MT, Rausch RN, Keeley ER. Thermal tolerance and metabolic physiology among redband trout populations in south-eastern Oregon. J Fish Biol 64:1-26, 2004.

Malthankar GV, White BK, Bhushan A., Daniels CK, Rodnick KJ, Lai JCK. Differential lowering by manganese treatment of activities of glycolytic and tricarboxylic acid (TCA) cycle enzymes investigated in neuroblastoma and astrocytoma cells is associated with manganese-induced cell death. Neurochem Res 29:709-717, 2004.

Gamperl AK, Rodnick KJ, Faust HA, Venn EC, Bennett MT, Crawshaw LH, Keeley ER, Powell MS, and Li HW. Metabolism swimming performance and tissue biochemistry of high desert redband trout (Oncorhynchus mykiss ssp.): Evidence for phenotypic differences in physiological function. Physiol Biochem Zool 75:413-431, 2002.

Swislocki ALM, Burgie ES, Rodnick KJ. Effects of ovariectomy on indices of insulin resistance, hypertension, and cardiac energy metabolism in middle-aged spontaneously hypertensive rats (SHR). Horm Metab Res 34:516-522, 2002.

Lacey JA, Rodnick KJ. Important considerations for methaemoglobin measurement in fish blood: assay choice and storage conditions. J Fish Biol 60:1155-1169, 2002.

LaPier TLK, Swislocki ALM, Clark RJ, Rodnick KJ. Voluntary running enhances insulin action in female spontaneously hypertensive rats. Am J Hypertens 14:708-715, 2001.


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