Contents lists available at ScienceDirect European Journal of Pharmacology journal homepage: www.elsevier.com/locate/ejphar Full length article Unravelling the intravenous and in situ vasopressin effects on the urinary bladder in anesthetized female rats: More than one vasopressin receptor subtype involved? Eduardo M. Cafarchio a , Luciana C. Auresco a , Luiz A. da Silva a , Itatiana F. Rodart c , Barbara do Vale a , Janaina S. de Souza b , Bruno B. Antonio a , Daniel P. Venancio a , Gisele Giannocco b , Patrik Aronsson d , Monica A. Sato a, ⁎ a Dept. Morphology and Physiology, Faculdade de Medicina do ABC, Santo Andre, SP, Brazil b Dept. Medicine, Universidade Federal de Sao Paulo Sao Paulo, Brazil c Human Reproduction and Genetics Center, Dept. Collective Health, Faculdade de Medicina do ABC, Santo Andre, SP, Brazil d Dept Pharmacology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden ARTICLE INFO Keywords: Intravesical pressure Urinary bladder Vasopressin Receptors ABSTRACT Urinary bladder dysfunctions show high prevalence in women. We focused to investigate the intravenous and in situ (topic) vasopressin effects on the bladder and also to characterize the vasopressin receptor subtypes in the bladder. Adult female Wistar rats anesthetized with isoflurane underwent to the cannulation of the femoral artery and vein, and also urinary bladder for mean arterial pressure, heart rate and intravesical pressure (IP) recordings, respectively. Doppler flow probe was placed around the renal artery for blood flow measurement. After baseline recordings, intravenous injection of saline or vasopressin at different doses (0.25, 0.5, 1.0 ng/ml/ kg of b.w.); or 0.1 ml of saline or 0.1 ml of vasopressin at different doses (0.25, 0.5, 1.0 ng/ml) was randomly dropped on the bladder. In another group of rats, the UB was harvest for gene expression by qPCR and also for protein expression by Western blotting of the vasopressin receptor subtypes. We observed that either intravenous or in situ vasopressin evoked a huge increase in the IP in a dose-dependent manner compared to saline, whilst no differences were observed in the cardiovascular parameters. The genes and the protein expression of V1a, V1b and V2 vasopressin receptors subtypes were found in the bladder. Intravenous injection of V1a or V2 receptor antagonist evoked a huge fall in IP and 30 min later, i.v or in situ vasopressin evoked responses on IP were significantly attenuated. Therefore, intravenous or in situ vasopressin increases the IP due to binding in V1a or V2 receptors localized in the bladder. 1. Introduction Bladder dysfunctions can cause social and mental discomfort and affect the well-being, and usually patients suffer in silence due to the difficulty of performing many normal activities in daily life. Dysfunctions of the lower urinary tract are frequent complaints, ac- counting for up to 40% in ambulatories of nephrology and urology (Kajiwara et al., 2004; Sureshkumar et al., 2009). The central control of the micturition is dependent on the Barrington´s nucleus (pontine micturition center), pontine urine storage center (PUSC) and periaqueductal gray matter (de Groat et al., 2005). Evidence has also shown that brain stem areas, primarily known by their involvement in cardiovascular regulation, can elicit changes in the pelvic nerves activities (Chen et al., 1993; Chen and Chai, 2002). Cholinergic activation of medullary neurons by carbachol injections into the fourth brain ventricle (4th V) increases plasma vasopressin (Cafarchio et al., 2016). Previous intravenous injection of V1 receptor antagonist abolishes the increase in the intravesical pressure elicited by carbachol into the 4th V (Cafarchio et al., 2016). These findings sug- gested that pathways from the medulla to the hypothalamus can also be involved in the control of the urinary bladder (Cafarchio et al., 2016). Vasopressin is a nonapeptide synthesized in the magnocellular neurons of the supraoptic (SON) and paraventricular (PVN) nuclei of the hypothalamus as well as in the parvocellular neurons of the PVN. https://doi.org/10.1016/j.ejphar.2018.07.024 Received 21 May 2018; Received in revised form 2 July 2018; Accepted 13 July 2018 ⁎ Correspondence to: Faculdade de Medicina do ABC, Dept. Morphology and Physiology, 2000 Lauro Gomes Ave., Vila Sacadura Cabral, Santo Andre, SP 09060- 870, Brazil. E-mail address: monica.sato@fmabc.br (M.A. Sato). European Journal of Pharmacology 834 (2018) 109–117 Available online 17 July 2018 0014-2999/ © 2018 Elsevier B.V. All rights reserved. T