My long term career goal is to develop an independent research program to investigate autonomic regulation of urinary function in health and disease. To enhance my research training, I seek additional experience with neuroanatomical and in vivo techniques for the purpose of quantifying bladder dysfunction mediated by an alteration in autonomic control mechanisms in diabetic states. I have assembled an expert advisory committee of leading bladder researchers and clinicians to oversee my development in these areas. I have also earned a commitment from the Department of Anatomy and Neurobiology at the University of Vermont that guarantees me access to the space and resources I will need to complete this training. This research proposal will test the hypothesis that altered ganglionic neurotransmission contributes to bladder dysfunction in diabetics. The hypothesis will be addressed by investigation of major pelvic ganglion (MPG) structure and function in murine models of diabetes. The MPG supplies efferent autonomic input to the genitourinary tract from sympathetic and parasympathetic nerves. Three important questions are addressed: what are the defining characteristics of diabetic uropathy and when do they present in genetic and nongenetic mouse models of diabetes? is diabetic bladder dysfunction associated with aberrant neuronal activity within the MPG? and, what affect does diabetes have on the neurochemical and morphological profile of the MPG? Under the guidance of Dr. Margaret Vizzard (sponsor), urodynamic function will be evaluated over time in inbred mice (C57BL/6J) made diabetic with streptozotocin-treatment as well as in mice genetically predisposed to diabetes (NOD/ ShiLtJ;BKS.Cg-m+/+Leprdb/J). Timepoints associated with onset and development of diabetic uropathy will be identified. Neuronal activity will be studied in the MPG of diabetic and non-diabetic animals using intracellular microelectrode technique. A comparison of the active and passive membrane properties and the efficacy of synaptic transmission, following stimulation of ganglionic inputs, will be made. Ganglion neuroanatomy will be defined using immunohistochemistry and confocal microscopy imaging techniques. Principle cholinergic and adrenergic MPG neurons that target the urinary bladder will be identified by retrograde labeling and cellular morphology will be quantified in diabetic and non-diabetics using morphometric technique. This work will provide valuable evidence as to the extent of MPG remodeling occurring with diabetic bladder dysfunction.
Currently, 20 million people are affected by diabetes in the United States: 7% of the total population. Diabetes can cause damage to nerves that are important in regulating the function of major organs including the heart, the stomach and the bladder. This project will determine which components of the nervous system are damaged by diabetes and lead to problems with urination.
|Tompkins, John D; Vizzard, Margaret A; Parsons, Rodney L (2013) Synaptic transmission at parasympathetic neurons of the major pelvic ganglion from normal and diabetic male mice. J Neurophysiol 109:988-95|
|Girard, Beatrice M; Merriam, Laura A; Tompkins, John D et al. (2013) Decrease in neuronal nicotinic acetylcholine receptor subunit and PSD-93 transcript levels in the male mouse MPG after cavernous nerve injury or explant culture. Am J Physiol Renal Physiol 305:F1504-12|
|Tompkins, John D; Girard, Beatrice M; Vizzard, Margaret A et al. (2010) VIP and PACAP effects on mouse major pelvic ganglia neurons. J Mol Neurosci 42:390-6|
|Hoover, Donald B; Tompkins, John D; Parsons, Rodney L (2009) Differential activation of guinea pig intrinsic cardiac neurons by the PAC1 agonists maxadilan and pituitary adenylate cyclase-activating polypeptide 27 (PACAP27). J Pharmacol Exp Ther 331:197-203|
|Tompkins, John D; Lawrence, Yancey T; Parsons, Rodney L (2009) Enhancement of Ih, but not inhibition of IM, is a key mechanism underlying the PACAP-induced increase in excitability of guinea pig intrinsic cardiac neurons. Am J Physiol Regul Integr Comp Physiol 297:R52-9|