代謝症候群老鼠膀胱中大麻素受體下降及其影響
陳奕宏、鄭瑞棠1,2、唐一清
國立成功大學醫學院附設醫院泌尿科；1奇美醫學中心醫學研究部；2長榮大學醫學研究所
Reduced cannabinoid receptors in bladder of metabolic syndrome ratS
I-Hung Chen , Juei-Tang Cheng1,2, Yat-Ching Tong
Department of Urology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan City, Taiwan; Department of Medical Research, Chi-Mei Medical Center, Tainan City, Taiwan1; Institute of Medical Sciences, Chang Jung Christian University, Tainan City, Taiwan2
Purpose: To study the influence of metabolic syndrome on cannabinoid receptors in rats’ bladder.
Materials and Methods: Male Sprague-Dawley rats were fed with high-fructose diet for nine weeks to induce metabolic syndrome. Another group was rats fed with normal chow. Metabolic syndrome associated profiles were measured. Bladder was harvested and Western blot, as well as RT-PCR tests, was applied for cannabinoid receptors expression. Pre-contracted bladder muscle strips were prepared in organ bath with acetylcholine or KCl. The effects of cannabionid receptor agonist on bladder strips were explored. The responses to protein kinase A (PKA) inhibitor and ATP-sensitive potassium channel (KATP) inhibitor were investigated.
Results: Metabolic syndrome was successfully induced in rats fed with high-fructose diet. Down-regulation of cannabinoid receptor protein and mRNA was found in metabolic syndrome rats. Pre-contracted bladder muscle strip tension decreased after cannabinoid receptor agonist treatment. The influence of cannabinoid receptor agonist on bladder muscle attenuated significantly in metabolic syndrome rats. Bladder muscle relaxation, which was induced by cannabinoid receptor agonist, was reduced after PKA inhibitor and KATP inhibitor treatment.
Conclusion: Cannabinoid receptors associated bladder relaxation might link to PKA and KATP pathway. The decreased effect of cannabinoid receptor on bladder muscle in metabolic syndrome rats might be related to down regulation of the receptor expression.