BACKGROUND: The present study was aimed at investigating whether there is a mechanism exerted by endogenous nitric oxide(NO) in the regulation of aquaporin(AQP) water channels in the kidney. METHODS: Male Sprague-Dawley rats were treated with N(G)-nitro-L-arginine methyl ester(L-NAME, 40 mg/L drinking water) to inhibit the endogenous generation of nitric oxide. Four weeks later, total abundance and shuttling of AQP2 proteins were determined in different regions of the kidney. RESULTS: Chronic inhibition of NO synthesis increased the expression of AQP2 channels in cortex, outer medulla, and inner medulla of the kidney. The AQP2 shuttling was not significantly altered, as evidenced by an unaltered ratio of AQP2 expression in the membrane fraction versus that in the cytoplasmic fraction. CONCLUSION: It is suggested that endogenous NO activity plays a tonic inhibitory role in the expression of AQP2 channels in the kidney.
Animals ; Aquaporin 2* ; Aquaporins* ; Cytoplasm ; Drinking ; Humans ; Kidney* ; Male ; Membranes ; Nitric Oxide* ; Rats* ; Rats, Sprague-Dawley

OBJECTIVES: Accurate diagnosis of the mechanism and origin site of paroxysmal supraventricular tachycardia(PSVT) can be made using electrophysiologic study(EPS). Recently, radiofrequency catheter ablation technique has been introduced and widely used for the definitive treatment of various forms of PSVT, thereby precise determination of the mechanism of PSVT can be possible. It has been known that atrioventricular reentry tachycardia (AVRT) using concealed bypass tract is more frequent than atrioventricular nodal reentry tachycardia (AVNRT) in Korea. But it is not certain that those studies represent actual distribution of PSVT in Korea. This study was designed to determine the mechanism and clinical characteristics of PSVT in Korea. METHODS: We investigated 136patients in whom electrophysiolosic study was performed from October 1992 through October 1994 at the Chonnam National University Hospital, the only tertiary referral center of the Kwangju-Chonnam area of Korea. RESULTS: 1) The electrophysiologic mechanism of PSVT was AVNRT in 44patients(32.4%), WPW syndrome in 46(33.8%), AVRT using concealed bypass tract in 40(29.4%), sinoatrial nodal reentry tachycardia (SANRT) in 4(2.9%), and automatic atrial tachycardia(AAT) in 2(1.5%), ensuing that AVNRT is most common mechanism of PSVT with no preexcitation during sinus rhythm. 2) Male is more frequent than female in AVNRT, WPW syndrome, and AVRT, which was most prominent in WPW syndrome. 3) The first episode of symptom occured at the age of 34.9 +/- 17.3 years in AVNRT, 25.5 +/- 13.3 years in WPW and 26.3 +/- 15.0 years in AVRT(p<0.05). There was no significant difference in the duration of symptom. The tachycardia rate in WPW syndrome was 183.6 +/- 23.9 per minute and AVRT was 186.7 +/- 38.0 per minute, which were faster than that of AVNRT(161.7 +/- 28.6/min)(p<0.05). 4) There was no significant difference in the presenting symptoms and in the provocation factors between AVNRT and AVRT. CONCLUSION: AVNIlT is most common mechanism of PSVT with no preexcitation during sinus rhythm, developed at older age than WPW syndorme and AVRT, and had lower tachycardia rate than WPW syndrome and AVRT.
Catheter Ablation ; Diagnosis ; Female ; Humans ; Jeollanam-do ; Korea ; Male ; Tachycardia ; Tachycardia, Atrioventricular Nodal Reentry ; Tachycardia, Sinoatrial Nodal Reentry ; Tachycardia, Supraventricular* ; Tertiary Care Centers ; Wolff-Parkinson-White Syndrome