In: Advances in Medicine and Biology - Volume 38 ISBN 978-1-62100-146-1 Editor: Leon V. Berhardt 2011 Nova Science Publishers, Inc. Chapter 8 PEPTIDERGIC REGULATION OF THE URINARY BLADDER FUNCTIONS Anna Tolekova 1 , Petya Hadzhibozheva 1 , Tsvetelin Georgiev 1 , Rosen Iliev 2 , Galina Ilieva 1 , Federica Pessina 3 , Reni Kalfin 4 1 Department of Physiology, Pathophysiology and Pharmacology, Medical Faculty, Trakia University, Stara Zagora, Bulgaria 2 Department of Propaedeutics of Internal Diseases, Medical Faculty, Trakia University, Stara Zagora, Bulgaria 3 Department of Neuroscience, Siena University, Siena, Italy 4 Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria ABSTRACT The regulation of the urinary bladder activity is an interesting scientific research field. Many mediators and modulators of the vegetative nerve system or locally generated ones are involved in the adjustment of the bladder function. However, despite its high prevalence and cost to society urinary incontinence remains poorly studied and poorly understood, as does the normal peptidergic control and functioning of the urinary bladder. Periodic bladder ischemia during obstructed micturition has been suggested to result in the partial denervation of the detrusor smooth muscle, through ischemia and reperfusion injury to the neurons within the bladder wall. This manuscript presents an overview on the peptidergic regulation of the urinary bladder functions and contractile activity by ghrelin, vasoactive intestinal peptide, angiotensins and vasopressin. Original results obtained by the authors regarding effects and mechanisms of ghrelin action on Angiotensin II and arginine-vasopressin mediated contractions of urinary bladder, as well as protection of detrusor nerves from experimental ischemia and reperfusion injury by vasoactive intestinal peptide are also discussed.