Modulatory Effects of Peptide Ghrelin on Urinary Bladder and Its Role in Diabetes

P. V. HADZIBOZHEVA1, M. I. LAZAROVA2, A. N. TOLEKOVA1 and R. E. KALFIN2
1 Trakia University, Department of Physiology, Pathophysiology and Pharmacology, Medical Faculty, BG – 6000 Stara Zagora, Bulgaria
2 Bulgarian Academy of Sciences, Department of Synaptic Signaling and Communications, Institute of Neurobiology, BG – 1113 Sofia, Bulgaria

Abstract

HADZIBOZHEVA, P. V., M. I. LAZAROVA, A. N. TOLEKOVA and R. E. KALFIN, 2014. Modulatory effects of peptide ghrelin on urinary bladder and its role in diabetes. Bulg. J. Agric. Sci., Supplement 1: 15–19

 

Plasma ghrelin levels manifest “biphasic changes” in diabetes mellitus. In order to investigate ghrelin effects and mechanisms of action in diabetes, fi rstly we should know how this peptide modulates urinary bladder muscles under normal conditions. We found no statistically signifi cant changes in contractile activity after application of ghrelin alone as compared to the spontaneous activity. The effects of ghrelin were displayed when it was applied in combination with other peptides. For example, 30 min after ghrelin application, the administration of Ang II did not lead to the typical tonic contractions occurring when only Ang II was administrated. The amplitude of the Ang II stimulated contractions was reduced from 1.90 ± 0.20 g to 0.78 ± 0.09 g in the presence of ghrelin (n = 21, P < 0.05). Based on these results we can assume that the urinary bladder possesses receptors for ghrelin, which are different from those in the digestive tract, with respect to the kind of intracellular signalling mechanism to which they are coupled.

Key words: ghrelin, urinary bladder, contractile activity, smooth muscle, diabetes
Abb reviations: Ang II – angiotensin II; GOAT – O-n-octanoylation at serine 3 through the enzyme ghrelin Oacyltransferase; AVP – vasopressin; AUC – area under the curve

 

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