Gaylen Lee Edwards

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University of Georgia
Veterinary Medicine
Physiology and Pharmacology
ProfessorAppointed: 1989

Mailing Address

711 Boyd Graduate Studies Bldg.
University of Georgia
Athens, Georgia 30602
United States

Contact Information

Phone: (706) 542-5854
Fax: (706) 542-0261
gedwards@uga.edu

Qualifications

Ph.D., Washington State University, Veterinary Science, 1986.
D.V.M., Washington State University, Veterinary Medicine, 1984.
M.S., University of Idaho, Veterinary Science, 1980.
B.S., Idaho State University, Zoology, 1978.

Expertise and Research Interests

The research in my laboratory focuses primarily on central neural control of energy balance. These studies focus on hindbrain nuclei that receive and relay afferent information to the forebrain such as the nucleus of the solitary tract, area postrema and pontine parabrachial nucleus. We have found that lesions of these nuclei produce marked alterations in an animal's food and fluid intake. Most likely by influencing function of limbic structures in the forebrain. Our current studies are aimed at understanding how these lesions result in a marked appetite for highly palatable foods. These experiments include neuroanatomical studies intended to gain a better understanding of the relationships of hindbrain neuronal populations that project to the forebrain, as well as the possible chemical nature of cells in these nuclei. For example, we have found that cannabinoids may influence food intake via actions in the hindbrain. This action may involve other neurotransmitters such as GABA, norepinephrine and dopamine.

Since the area postrema is a circumventricular organ and lacks a blood brain barrier, it is ideally suited to monitor blood borne humoral signals. In addition, primary afferent neurons that innervate the viscera, including the stomach, intestines,liver and pancreas, are reported to synapse in the nucleus of the solitary tract adjacent to the area postrema. Thus, this region is strategically situated to monitor the status of numerous visceral systems, both neurally and humorally, and in turn influence food intake. Similarly, this region may influence autonomic motor function. Recent experiments involving rats with lesions of the area postrema and adjacent nucleus of the solitary tract indicate that this area is important in the autonomic regulation of abdominal viscera. We are particularly interested in these experiments as they may provide clues to mechanisms by which circulating factors might modulate gastrointestinal motility and function.

In summary, we believe the hindbrain receives information from the periphery that influences diet selection, food intake and gastrointestinal function. This information is critical to overall energy balance. Given the obesity epidemic in the United States, these studies are important to our understanding of the mechanisms controlling intake of highly palatable, energy rich foods.

Other Expertise

We maintain an interest in neural regulation of fluid balance and sodium appetite. Hindbrain systems have profound effects on these functions. We also have a strong interest in measures of neurochemicals such as catecholamines, indolamines and amino acids.

Future Research

Future research is aimed at evaluating forebrain systems involved in appetite and reward. These systems contribute to diet selection and response to macronutrients in various models of obesity.

Industrial Relevance

The area postrema is a circumventricular organ and accessible to circulating factors such as pharmacological agents. Understanding how this structure influences appetite and metabolism as well as the neurochemicals acting in this region will lead to agents that affect this brain structure to influence foodintake and energy balance.

Keywords

COS Keywords:

Alcohol or Alcoholism, Anxiety Disorders, Behavioral Pharmacology, Diabetes, Eating Disorders, Metabolism, Neuroanatomy, Neuroscience, Obesity.

Additional Terms:

Adipose Signals, Alcohol, Cannabinoids, Drinking, Drinking Behavior, Electrolyte, Fluid Balance, Food Intake, Food Reward, Hindbrain, Ingestion, Ingestive Behavior, Intake, Motivation for Food, Neuroscience, Obesity, Water Intake.

Languages

(Reading, Writing, Speaking)

English: (Fluent, Fluent, Fluent)

Memberships

American Association for the Advancement of Science
American Physiological Society
North American Association for the Study of Obesity
Sigma Xi, The Scientific Research Society
Society for Neuroscience
Society for the Study of Ingestive Behavior

Previous Positions

1986-1989, Postdoctoral Fellow, University of Iowa

Funding Received

  • Pfizer, Inc.: Identification of Adipose Satiety Factor, a Putative Feedback Signal for the Regulation of Body Energy., $73,250, Oct 1999 to Sep 2000.
  • Hill's Pet Nutrition: Effects of Conjugated Linoleic Acid Supplementation in Dogs, $70,000, Oct 1997 to Oct 1998.
  • Hill's Pet Nutrition: Effects of Nutritional Supplementation in Dogs, $14,688, Oct 1996 to Sep 1997.
  • National Institutes of Health (NIH): Mechanism of Dietary Effects on Macronutrient Selection, $124,488, May 1992 to Apr 1995.
  • Amylin Pharmaceuticals, Inc.: Afferent Mediation of Amylin Action, $46,880, Mar 1997 to Jul 1998.
  • American Diabetes Association: Role of the Dorsomedial medulla Oblongata in Amylin Action on Gastrointestinal Activity and Food Intake., $146,671, Jul 1998 to Dec 2000.
  • Univeristy of Georgia Veterinary Medical Experiment Station: Evaluation of Combined Fenfluramine/DHEA Treatment as a Possible Therapy for Obesity., $12,500, Jul 1995 to May 1997.
  • University of Georgia Biotechnology Award: Transgenic Rodents for Body Weight Regulation, $93,685, Jul 1994 to Jun 1996.
  • University of Georgia Biotechnology Award: In Situ Hybridization and Immunohistochemistry of Neuropeptides Involved in Energy Balance Regulation, $61,330, Jul 1991 to Jun 1993.
  • University of Georgia Veterinary Medical Experiment Station: Serotonergic Influences on Ingestive Behavior and Response to Toxicosis, $8,633, Jul 1990 to Jun 1991.
  • American Heart Association: Mechanisms of Enhanced Natriuresis Occuring after Dorsal Hindbrain Lesions that are Reportedly Antihypertensive, $21,652, Jul 1990 to Jun 1991.
  • National Institutes of Health (NIH): Hindbrain Involvement in Water and Sodium Intake, $349,906, Jan 1991 to Dec 1996.
  • University of Georgia Research Foundation: Role of the Dorsomedial Medulla in Glucose Regulation, $5,536, Jan 1990 to Dec 1990.
  • National Institutes of Health (NIH): Ingestive Peptide Control of Alcohol Intake, $100,000, Aug 2001 to Dec 2003.
  • National Institutes of Health (NIH): Metabolic Regulation of Growth and Development, $574,590, Apr 1997 to Mar 2001.

Publications

  • Clegg DJ, Edwards GL, Martin RJ, Central insulin potentiates eating elicited by 2-deoxy-D-glucose, Physiology and Behavior, 78(2), 331-6, February 2003 Abstract
  • Miller CC, Martin RJ, Whitney ML, Edwards GL, Intracerebroventricular injection of fructose stimulates feeding in rats, Nutritional Neuroscience, 5(5), 359-62, October 2002 Abstract
  • Miller CC, Holmes PV, Edwards GL, Area postrema lesions elevate NPY levels and decrease anxiety-related behavior in rats, Physiology and Behavior, 77(1), 135-40, September 2002 Abstract
  • Phositlimpagul A, Edwards GL, Azain MJ, Hepatic vagotomy disrupts somatotropin-induced protein selection, Physiology and Behavior, 75(1-2), 193-200, February 2002 Abstract
  • Froetschel MA, Azain MJ, Edwards GL, Barb CR, Amos HE, Opioid and cholecystokinin antagonists alleviate gastric inhibition of food intake by premeal loads of casein in meal-fed rats, Journal of Nutrition, 131(12), 3270-6, December 2001 Abstract
  • Dishman RK, Hong S, Soares J, Edwards GL, Bunnell BN, Jaso-Friedmann L, Evans DL, Activity-wheel running blunts suppression of splenic natural killer cell cytotoxicity after sympathectomy and footshock, Physiology and Behavior, 71(3-4), 297-304, November 2000 Abstract
  • DePrato Primeaux S, Holmes PV, Martin RJ, Dean RG, Edwards GL, Experimentally induced attenuation of neuropeptide-Y gene expression in transgenic mice increases mortality rate following seizures, Neuroscience Letters, 287(1), 61-4, June 2000 Abstract
  • Soares J, Holmes PV, Renner KJ, Edwards GL, Bunnell BN, Dishman RK, Brain noradrenergic responses to footshock after chronic activity-wheel running., Behavioral Neuroscience, 113(3), 558-66, June 1999 Abstract
  • Edwards GL, Power JD, The role of brain-gut peptides in the control of sodium appetite, Annals of the New York Academy of Sciences, 897, 192-7, 1999 Abstract
  • Wang T, Edwards G L, Baile C A, Glucagon-like peptide-1 (7-36) amide administered into the third cerebroventricle inhibits water intake in rats., Proceedings of The Society for Experimental Biology and Medicine, 219(1), 85-91, October 1998 Abstract
  • Edmonds BK, Edwards GL, Dorsomedial hindbrain participation in glucoprivic feeding response to 2DG but not 2DG-induced hyperglycemia or activation of the HPA axis., Brain Research, 801(1-2), 21-8, 10 Aug 1998 Abstract
  • Grossman B M, Hobbs J K, Edwards G L, Martin R J, Dietary fat type influences protein consumption in rats given 8-hydroxy-2-(Di-n-propylamino)tetralin., Physiology and Behavior, 63(5), 745-50, March 1998 Abstract
  • He B, White B D, Edwards G L, Martin R J, Longer-term fourth ventricular 5-thioglucose infusion increases body fat in the rat., Proceedings of The Society for Experimental Biology and Medicine, 217(2), 168-72, February 1998 Abstract
  • He B, White B D, Edwards G L, Martin R J, Neuropeptide Y antibody attenuates 2-deoxy-D-glucose induced feeding in rats., Brain Research, 781(1-2), 348-50, 19 Jan 1998 Abstract
  • Wang T, Edwards G L, Differential effects of dorsomedial medulla lesion size on ingestive behavior in rats., American Journal of Physiology, 273(4 Pt 2), R1299-308, October 1997 Abstract
  • Edwards G L, White B D, He B, Dean R G, Martin R J, Elevated hypothalamic neuropeptide Y levels in rats with dorsomedial hindbrain lesions., Brain Research, 755(1), 84-90, 25 Apr 1997 Abstract
  • Sun M, Martin R J, Edwards G L, ICV beta-hydroxybutyrate: effects on food intake, body composition, and body weight in rats., Physiology and Behavior, 61(3), 433-6, March 1997 Abstract
  • Wang T, Edwards G L, Enhanced water intake after asymmetric hindbrain lesions., Physiology and Behavior, 60(3), 733-9, September 1996 Abstract
  • White B D, Edwards G L, Martin R J, Interaction of type I and type II corticosteroid receptor stimulation on carcass energy and carcass water., American Journal of Physiology, 270(5 Pt 2), R1099-108, May 1996 Abstract
  • Edmonds B K, Edwards G L, The area postrema is involved in paraquat-induced conditioned aversion behavior and neuroendocrine activation of the hypothalamic-pituitary-adrenal axis., Brain Research, 712(1), 127-33, 11 Mar 1996 Abstract
  • Edwards G L, White B D, Zhao W, He B, Dean R G, Martin R J, Lesions of the area postrema/adjacent nucleus of the solitary tract result in enhanced hypothalamic neuropeptide Y levels., Annals of The New York Academy of Sciences, 739, 337-8, 31 Oct 1994 Abstract
  • Edwards G L, Johnson A K, Peuler J D, Enhanced bradycardia but not renal sympathoinhibition during hemorrhage in rats with area postrema lesions., American Journal of Physiology, 267(2 Pt 2), H569-73, August 1994 Abstract
  • Grossman B M, White B D, Edwards G L, Martin R J, Vagotomy and mercaptoacetate influence the effect of dietary fat on macronutrient selection by rats., Journal of Nutrition, 124(6), 804-9, June 1994 Abstract
  • White B D, Dean R G, Edwards G L, Martin R J, Type II corticosteroid receptor stimulation increases NPY gene expression in basomedial hypothalamus of rats., American Journal of Physiology, 266(5 Pt 2), R1523-9, May 1994 Abstract
  • Edwards G L, Power J D, Attenuation of 8-OH-DPAT induced feeding after lesions of the area postrema/immediately adjacent nucleus of the solitary tract., Brain Research, 628(1-2), 321-6, 19 Nov 1993 Abstract
  • Edwards G L, Beltz T G, Power J D, Johnson A K, Rapid-onset "need-free" sodium appetite after lesions of the dorsomedial medulla., American Journal of Physiology, 264(6 Pt 2), R1242-7, June 1993 Abstract
  • Hay M, Edwards G L, Lindsley K, Murphy S, Sharma R V, Bhalla R C, Johnson A K, Increases in cytosolic Ca2+ in rat area postrema/mNTS neurons produced by angiotensin II and arginine-vasopressin., Neuroscience Letters, 151(2), 121-5, 19 Mar 1993 Abstract
  • Mizinga K M, Thompson F N, Stuedemann J A, Edwards G L, Neural dopamine D2 receptors in rats fed endophyte-infected fescue seed., Drug and Chemical Toxicology, 16(3), 307-19, 1993 Abstract
  • Johnson A K, Zardetto-Smith A M, Edwards G L, Integrative mechanisms and the maintenance of cardiovascular and body fluid homeostasis: the central processing of sensory input derived from the circumventricular organs of the lamina terminalis., Progress In Brain Research, 91, 381-93, 1992 Abstract
  • Edwards G L, Johnson A K, Enhanced drinking after excitotoxic lesions of the parabrachial nucleus in the rat., American Journal of Physiology, 261(4 Pt 2), R1039-44, October 1991 Abstract
  • Cunningham J T, Sullivan M J, Edwards G L, Farinpour R, Beltz T G, Johnson A K, Dissociation of experimentally induced drinking behavior by ibotenate injection into the median preoptic nucleus., Brain Research, 554(1-2), 153-8, 19 Jul 1991 Abstract
  • Peuler J D, Edwards G L, Schmid P G, Johnson A K, Area postrema and differential reflex effects of vasopressin and phenylephrine in rats., American Journal of Physiology, 258(4 Pt 2), H1255-9, April 1990 Abstract
  • Edwards, G.L. E.E. Ladenheim and R.C. Ritter. Dorsal hindbrain participation in cholecystokinin-induced satiety. American Journal of Physiology 251: R971-R977, 1986
  • Edwards, G.L. and R.C. Ritter. Area postrema lesions increase drinking to angiotensin and extracellular dehydration. Physiology and Behavior. 29: 943-947, 1982
  • Edwards, G.L. and R.C. Ritter. Ablation of the area postrema causes exaggerated consumption of preferred foods in the rat. Brain Research 216: 265-276, 1981
  • Edwards, G.L., J.T. Cunningham, T.G. Beltz and A.K. Johnson. Neuropeptide gamma-immunoreactive neurons in the caudal medulla project to the median preoptic nucleus. Neuroscience Letters 105: 19-26, 1989

Profile Details

Last Updated: 9/3/2003

COS Expertise ID #232320
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