title: Role of PKC and CaV1.2 in detrusor overactivity in a model of obesity associated with insulin resistance in mice.
abstract: Obesity/metabolic syndrome are common risk factors for overactive bladder. This study aimed to investigate the functional and molecular changes of detrusor smooth muscle (DSM) in high-fat insulin resistant obese mice, focusing on the role of protein kinase C (PKC) and Ca(v)1.2 in causing bladder dysfunction. Male C57BL/6 mice were fed with high-fat diet for 10 weeks. In vitro functional responses and cystometry, as well as PKC and Ca(v)1.2 expression in bladder were evaluated. Obese mice exhibited higher body weight, epididymal fat mass, fasting glucose and insulin resistance. Carbachol (0.001-100 µM), α,β-methylene ATP (1-10 µM), KCl (1-300 mM), extracellular Ca(2+) (0.01-100 mM) and phorbol-12,13-dibutyrate (PDBu; 0.001-3 µM) all produced greater DSM contractions in obese mice, which were fully reversed by the Ca(v)1.2 blocker amlodipine. Cystometry evidenced augmented frequency, non-void contractions and post-void pressure in obese mice that were also prevented by amlodipine. Metformin treatment improved the insulin sensitivity, and normalized the in vitro bladder hypercontractility and cystometric dysfunction in obese mice. The PKC inhibitor GF109203X (1 µM) also reduced the carbachol induced contractions. PKC protein expression was markedly higher in bladder tissues from obese mice, which was normalized by metformin treatment. The Ca(v)1.2 channel protein expression was not modified in any experimental group. Our findings show that Ca(v)1.2 blockade and improvement of insulin sensitization restores the enhanced PKC protein expression in bladder tissues and normalizes the overactive detrusor. It is likely that insulin resistance importantly contributes for the pathophysiology of this urological disorder in obese mice.
authors.affiliation: Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil.
authors.forename: Luiz O
authors.initials: LO
authors.lastname: Leiria
authors.forename: Carolina
authors.initials: C
authors.lastname: Sollon
authors.forename: Marina C
authors.initials: MC
authors.lastname: Calixto
authors.forename: Letícia
authors.initials: L
authors.lastname: Lintomen
authors.forename: Fabíola Z
authors.initials: FZ
authors.lastname: Mónica
authors.forename: Gabriel F
authors.initials: GF
authors.lastname: Anhê
authors.forename: Gilberto
authors.initials: G
authors.lastname: De Nucci
authors.forename: Angelina
authors.initials: A
authors.lastname: Zanesco
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Grant
authors.forename: Edson
authors.initials: E
authors.lastname: Antunes
mesh_terms: D050154:Adiposity / Q000187:drug effects; D017311:Amlodipine / Q000494:pharmacology; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000378:metabolism*; D002122:Calcium Chloride / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D004195:Disease Models, Animal; D004822:Epididymis / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology; D007333:Insulin Resistance; D008297:Male; D008687:Metformin / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D008820:Mice, Obese; D009119:Muscle Contraction / Q000187:drug effects; D009765:Obesity / Q000150:complications* / Q000201:enzymology / Q000503:physiopathology*; D009929:Organ Size / Q000187:drug effects; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D013851:Thinness / Q000150:complications / Q000503:physiopathology; D053201:Urinary Bladder, Overactive / Q000150:complications* / Q000201:enzymology / Q000503:physiopathology*
chemical_list: C514350:CACNA1C protein, mouse; D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D007328:Insulin; D017311:Amlodipine; D015240:Phorbol 12,13-Dibutyrate; D011189:Potassium Chloride; D002217:Carbachol; D008687:Metformin; D011493:Protein Kinase C; D002122:Calcium Chloride