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Gestational changes in nitric oxide synthase activity in rat placenta
P3-10 GESTATIONAL CHANGES IN NITRIC OXIDE SYNTHASE ACTIVITY IN RAT PLACENTA MyatThanda 1, S. Saheki 2, H. Kitagawa 1, S. Matsuura I I) Dept. of Obstetrics and Gynecology 2) Dept. of Laboratory Medicine, Univ., Ehime Japan
School of Medicine,
Ehime
Adaptational changes of maternal cardiovascular system occur in pregnancy. Nitric Oxide, synthesized from terminal guanidino-nitrogen atom of L-arginine by nitric oxide synthase (NOS), maintains constant basal vasodilator tone in systemic and local circulation. Increased urine output of NO was found in normal pregnancy of rats and the administration of L-arginine analogue to pregnant rats suppressed biosynthesis of NO and induced preeclampsia-like signs in fetus. Preeclampsia is primarily a placental disease and systemic endothelial cell damage due to the release of factor(s) from the placenta bed was supposed to play a role in the pathophysiology of pregnancy induced hypertension. Recently, NOS of the vascular and trophoblastic tissues of human placenta was characterized as the endothelial isoform. To understand more about the placental NOS and find its possible physiological role, we studied NOS in rat placentas of different gestational ages. Rat placentas of different gestational ages, day5, dayl0, dayl5 and day21, were collected for the NOS activity assay. NOS activities were determined by 3H-citrulline conversion assay in both soluble and particulate fractions in the presence or absence of calcium/calmodulin. NOS activities changed in different gestational ages. The highest activity was found on day5 placentas: 5.92 ± 0.75 pmol/min/mg protein in the particulate fractions and 3.39 ± 0.44 pmol/min/mg protein in the soluble fractions in the presence of calcium/calmodulin (mean ± SEM, n=7). Calcium/calmodulindependent NOS activities in the soluble and particulate fractions progressively declined during gestation and the lowest a c t i v i t i y was found on full term placentas on day21: 1.66 ± 0.28 pmol/min/mg protein in the particulate fractions and 0.58 ± 0.07 pmol/min/mg protein in the soluble fractions in the presence of calcium/calmodulin (mean ± SEM, n=4). Partial characterization of the enzyme showed the similar enzyme characteristics to those of the endothelial isoform. The physiological significance of gestational changes in NOS activity in placenta is not known. We could assume that the requirement of NO and its importance in fetoplacental circulation to maintain basal vascular tone or other possible functions, it carries out locally, might change during pregnancy. Impaired or increased production of NO altered from normal physiological course might associate with the development of feto-placental disdrders.
P3-11 PROTECTIVE EFFECt OF LIPOSOME-ENTRAPFF~ L-ARGININE AGAINST ISCHFJIA-REPERFUSION INJURY OF ISOLATED PERFUSED RAT HEART J. tYang, Q.trian,D.G. ~i,S.Y. ZDon8,L.¥.ZDong,J.~rans, C.S. ZTans. 1) Dept. of Pathophysiolosy, Zibo No. 2 2edical School, Zibo,P.R. China; 2) Inst. of Basal Cardiovascular
Research,Beijin8
Medical U n i v e r s i t y , B e i j i n g , P . R . C h i n a
E n d o t h e l i u a - d e r i v e d r e l a x i n g f a c t o r (EDRF)which i s one of the r e g u l a t o r y s u b s t a n c e s r e l e a s e from endothelium, may play an important regulatory role in local homeoslasis of circulation systems. Ischemia-reperfusion (I/R) of various vascular beds leads to an impairment of endothelial cells function, including a decrease in the release of EDRF. That was one of main pathogenetic factors in I/ R damage. The aim of the p r e s e n t s t u d y was to i n v e s t i g a t e , t h e p r o t e c t i v e e f f e c t s of l i p o s o m e - c a r r i e d L - a r g i n i n e ( L - A r g ) a s a i n s t I / R damage in i s o l a t e d p e r f u s e d rat h e a r t . T w e n t y - f o u r male rat h e a r t s aortic ertrograde perfused on Lansendorff apparatus w i t h K-H solution ( 9 5 ~ 0 2 : 5 X C 0 2 37"C),and which were a l l o w e d to s t a b i l i z e f o r 15 min and then d i v i d e d i n t o 3 groups. ( n=8 f o r each group) : I / R group ( w i t h K-H "solution e q u i l i b r a t e d w i t h a i r at l m l / m l n r e c l r l a t i o n f o r 50 mln, and w i t h r e o x y g e n a t i o n p e r f u s l o n f o r 10 min )0L-Arg group and L - A r g - l i p i s o m e group ( i s c h e m l c p e r f u s i o n s o l u t i o n c o n t a i n of 1 mmol/L f r e e L-Ar$ or L - A r g - l i p o s o m e , r e s p e c t i v e l y ) . P e r f u s i o n of i s c h e m i c h e a r t s w i t h 1. mmol/L L - A r g - l l p o s o m e s i g n i f i c a n t l y inhibited .the r e p e r f u s l o n induced an i n c r e a s e of myocardiao MDA i 95.99+-7.94 vs 1 1 7 . 1 5 + - 1 6 . 5 2 n m o l / $ w w , p <0.05) and m i t o c h o n d r l a l c a l c i u m ( 0 . 8 4 + - 0 . 0 8 vs 2 . 8 0 + - 0 . 2 7 u$/mgPr, P < 0 . 0 1 ) , markedly a l l e v i a t e d l e a k a g e of intracellular enzymesc L D N : I . 5 0 + - 0 , 0 6 vs 3 . 1 1 + - 0 . 1 3 U/min,P
487
School of Medicine,
Ehime
Adaptational changes of maternal cardiovascular system occur in pregnancy. Nitric Oxide, synthesized from terminal guanidino-nitrogen atom of L-arginine by nitric oxide synthase (NOS), maintains constant basal vasodilator tone in systemic and local circulation. Increased urine output of NO was found in normal pregnancy of rats and the administration of L-arginine analogue to pregnant rats suppressed biosynthesis of NO and induced preeclampsia-like signs in fetus. Preeclampsia is primarily a placental disease and systemic endothelial cell damage due to the release of factor(s) from the placenta bed was supposed to play a role in the pathophysiology of pregnancy induced hypertension. Recently, NOS of the vascular and trophoblastic tissues of human placenta was characterized as the endothelial isoform. To understand more about the placental NOS and find its possible physiological role, we studied NOS in rat placentas of different gestational ages. Rat placentas of different gestational ages, day5, dayl0, dayl5 and day21, were collected for the NOS activity assay. NOS activities were determined by 3H-citrulline conversion assay in both soluble and particulate fractions in the presence or absence of calcium/calmodulin. NOS activities changed in different gestational ages. The highest activity was found on day5 placentas: 5.92 ± 0.75 pmol/min/mg protein in the particulate fractions and 3.39 ± 0.44 pmol/min/mg protein in the soluble fractions in the presence of calcium/calmodulin (mean ± SEM, n=7). Calcium/calmodulindependent NOS activities in the soluble and particulate fractions progressively declined during gestation and the lowest a c t i v i t i y was found on full term placentas on day21: 1.66 ± 0.28 pmol/min/mg protein in the particulate fractions and 0.58 ± 0.07 pmol/min/mg protein in the soluble fractions in the presence of calcium/calmodulin (mean ± SEM, n=4). Partial characterization of the enzyme showed the similar enzyme characteristics to those of the endothelial isoform. The physiological significance of gestational changes in NOS activity in placenta is not known. We could assume that the requirement of NO and its importance in fetoplacental circulation to maintain basal vascular tone or other possible functions, it carries out locally, might change during pregnancy. Impaired or increased production of NO altered from normal physiological course might associate with the development of feto-placental disdrders.
P3-11 PROTECTIVE EFFECt OF LIPOSOME-ENTRAPFF~ L-ARGININE AGAINST ISCHFJIA-REPERFUSION INJURY OF ISOLATED PERFUSED RAT HEART J. tYang, Q.trian,D.G. ~i,S.Y. ZDon8,L.¥.ZDong,J.~rans, C.S. ZTans. 1) Dept. of Pathophysiolosy, Zibo No. 2 2edical School, Zibo,P.R. China; 2) Inst. of Basal Cardiovascular
Research,Beijin8
Medical U n i v e r s i t y , B e i j i n g , P . R . C h i n a
E n d o t h e l i u a - d e r i v e d r e l a x i n g f a c t o r (EDRF)which i s one of the r e g u l a t o r y s u b s t a n c e s r e l e a s e from endothelium, may play an important regulatory role in local homeoslasis of circulation systems. Ischemia-reperfusion (I/R) of various vascular beds leads to an impairment of endothelial cells function, including a decrease in the release of EDRF. That was one of main pathogenetic factors in I/ R damage. The aim of the p r e s e n t s t u d y was to i n v e s t i g a t e , t h e p r o t e c t i v e e f f e c t s of l i p o s o m e - c a r r i e d L - a r g i n i n e ( L - A r g ) a s a i n s t I / R damage in i s o l a t e d p e r f u s e d rat h e a r t . T w e n t y - f o u r male rat h e a r t s aortic ertrograde perfused on Lansendorff apparatus w i t h K-H solution ( 9 5 ~ 0 2 : 5 X C 0 2 37"C),and which were a l l o w e d to s t a b i l i z e f o r 15 min and then d i v i d e d i n t o 3 groups. ( n=8 f o r each group) : I / R group ( w i t h K-H "solution e q u i l i b r a t e d w i t h a i r at l m l / m l n r e c l r l a t i o n f o r 50 mln, and w i t h r e o x y g e n a t i o n p e r f u s l o n f o r 10 min )0L-Arg group and L - A r g - l i p i s o m e group ( i s c h e m l c p e r f u s i o n s o l u t i o n c o n t a i n of 1 mmol/L f r e e L-Ar$ or L - A r g - l i p o s o m e , r e s p e c t i v e l y ) . P e r f u s i o n of i s c h e m i c h e a r t s w i t h 1. mmol/L L - A r g - l l p o s o m e s i g n i f i c a n t l y inhibited .the r e p e r f u s l o n induced an i n c r e a s e of myocardiao MDA i 95.99+-7.94 vs 1 1 7 . 1 5 + - 1 6 . 5 2 n m o l / $ w w , p <0.05) and m i t o c h o n d r l a l c a l c i u m ( 0 . 8 4 + - 0 . 0 8 vs 2 . 8 0 + - 0 . 2 7 u$/mgPr, P < 0 . 0 1 ) , markedly a l l e v i a t e d l e a k a g e of intracellular enzymesc L D N : I . 5 0 + - 0 , 0 6 vs 3 . 1 1 + - 0 . 1 3 U/min,P
487