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Identification of presumptive messenger RNA for the heavy chain of cardiac myosin
31 50.
I N F L U E N C E OF E L E C T R I C A L L Y I N D U C E D AND A C O N I T I N E I N D U C E D A R R H Y T H M I A S ON THE P R O S T A G L A N D I N (PG) E F F L U X OF C O R O N A R Y SINUS B L O O D IN DOGS. H.-J. Mest, Ch. Taube, W. F S r s t e r , D e p a r t m e n t of P h a r m a c o logy, M a r t i n - L u t h e r - U n i v e r s i t y , H a l l e / S a a l e , GDR. The PG e f f l u x in the c a n i n e c o r o n a r y sinus b l o o d was e s t i m a t e d r a d i o i m m u n o l o g i c a l l y after e l e c t r i c a l ly i n d u c e d t a c h y a r r h y t h m i a s and e x t r a s y s t o l e s and after a c o n i t i n e i n d u c e d a r r h y t h m i a s , r e s p e c t i v e l y . T a c h y a r r h y t h m i a s w i t h an i n c r e a s e in f r e q u e n c y of 53% p r o d u c e d an i n c r e a s e of PGE in c o r o n a r y sinus b l o o d of 61% (p<0.01) and of PGF2~ of 67% (p<0.05). A f t e r e x t r a s y s t o l e s there was an i n c r e a s e of the e f f l u x of PGE of 28% (p<0.05) and of PGF~ of i4% (n.s.). The PG e f f l u x in c o r o n a r y sinus ~ o o d was nearly unchanged after aconitine without arrhythmia. However, the PG e f f l u x was i n c r e a s e d a f t e r a r r h y t h m i a had o c c u r r e d , e s p e c i a l l y after v e n t r i c u l a r t a c h y a r r h y t h m i a , v e n t r i c u l a r t a c h y c a r d i a and v e n t r i c u l a r flutter. The e f f l u x of PGE was r a i s e d m o r e than t e n f o l d and of PGF2e m o r e than twofold. The e n h a n c e m e n t of the PG e f f l u x after e x p e r i m e n t a l l y i n d u c e d a r r h y t h m i a s s u g g e s t s a feed b a c k m e c h a n i s m of PGs a g a i n s t a r r h y t h m i c i n f l u e n c e s .
51.
I D E N T I F I C A T I O N OF P R E S U M P T I V E M E S S E N G E R R N A F O R THE H E A V Y C H A I N OF C A R D I A C MYOSIN. J.M. Moalic, P. Padieu, G r o u p e de R e c h e r c h e : D i f f ~ r e n c i a tion B i o c h i m i q u e et C a n c ~ r o g ~ n ~ s e de C e l l u l e s E u c a ryotes en culture. F a c u l t ~ de M ~ d e c i n e , 21033 Dijon, France. T e r m i n a l c a r d i a c d i f f e r e n t i a t i o n of p r e s u m p t i v e m y o b l a s t s is a s s o c i a t e d w i t h the e x p r e s s i o n of n e w b i o s y n t h e t i c p r o g r a m m e s for s p e c i f i c m R N A t r a n s l a tion and e l a b o r a t i o n of the c o n t r a c t i l e a p p a r a t u s . C u l t u r e s of b e a t i n g h e a r t cells f r o m n e w b o r n rat p r o v i d e d a m o d e l for the s t u d y of t r a n s c r i p t i o n of c y t o p l a s m i c RNA and d e t e r m i n a t i o n of m e s s e n g e r R N A e x p r e s s i o n in r e l a t i o n to cell c y c l e and c u l t u r e development. S e p a r a t i o n and i d e n t i f i c a t i o n of c y t o p l ~ s m i c R N A h a v e b e e n c a r r i e d out by a c o m b i n a t i o n of O H - u r i d i n e p u l s e labeling, RNA e x t r a c t i o n , s e d i m e n t a t i o n grad i e n t f r a c t i o n a t i o n and h y b r i d i z a t i o n of p o l y ( A ) c o n t a i n i n g RNA to p o l y u r i d i l i c a c i d d e p o s i t e d on fiber glass filters.
32 R e s u l t s show that h e a r t cells r e a c h i n g c o n f l u e n c y at day-3 in c u l t u r e s y n t h e s i z e s e v e r a l p o l y ( A ) - m R N A species. A m o n g t h e m is a c o n s p i c u o u s peak of poly(A)m R N A which, f r o m its w e l l - d e f i n e d l o c a t i o n b e t w e e n 18S and 28S r i b o s o m a l RNA, can be i d e n t i f i e d as the m e s s e n g e r RNA for the h e a v y c h a i n of cardiac myosin.
52.
A L T E R A T I O N S OF THE P O S T A N O X I C R E C O V E R Y OF THE I N T R A C E L L U L A R R E D O X STATE AS O B S E R V E D IN E A R L Y STAGES OF RAT HEART H Y P E R T R O P H Y . J. Moravec, M. Laplace, G. Renault, U n i t ~ de R e c h e r c h e s de P a t h o l o g i e C a r d i o v a s c u l a i r e , I N S E R M U2, H6pital L ~ o n Bernard, 94450 L i m e i l - B r ~ v a n n e s , France. The c a p a c i t y of i s o l a t e d p e r f u s e d h e a r t s (Langendorff preparation) to o x i d i z e an e x c e s s of N A D H has b e e n t e s t e d by m e a n s of s u r f a c e f l u o r i m e t r y (365 and 470 nm). The k i n e t i c s of the state 5 - t o - s t a t e 3 t r a n s i t i o n has b e e n m o n i t o r e d 2 or 8 days after the b a n d i n g of the aorta and the r e s u l t s c o m p a r e d w i t h those o b t a i n e d on h e a l t h y p r e p a r a t i o n s . The m o s t imp o r t a n t d a t a are the following: (i) the a m p l i t u d e of the signal (PdN r e d u c t i o n ) , as o b s e r v e d 1 min of the anoxic p e r f u s i o n , is c o m p a r a b l e in all groups examined. It equals to 186, 185 and 170% of the a e r o b i c steady state signal in controls, 2 days and 8 daysl a s t i n g stenoses; (2) the time n e c e s s a r y to reach n o r m o x i c r e d o x c o n d i t i o n s is 38.5, 28.5 and 59.25 sec in the three groups e x a m i n e d ; (3) the c o r r e s p o n d i n g m a x i m a l rates of the r e o x i d a t i o n (% of a n o x i c signal/sec) are the following: 3.71, 6.58 and 2.81 per cent/sec. T h e s e r e s u l t s s u g g e s t there is, in h y p e r t r o p h i e d m y o c a r d i u m , a t r a n s i e n t p e r i o d of i m p r o v e d r e s p i r a tory activity, f o l l o w e d by an i m p a i r m e n t of m i t o c h o n d r i a l function. The s i g n i f i c a n c e of the above d a t a for the e t i o l o g y of c o n t r a c t i l e failure w i l l be discussed.
53.
P R O T E C T I V E E F F E C T OF P I R I D O X I L A T E ON H Y P O X I C HEART. P.R. Moret, U. Lutzen, C a r d i a c M e t a b o l i s m L a b o r a t o r y , C e n t e r of C a r d i o l o g y , Geneva, Switzerland. The p r o t e c t i v e a c t i o n of p i r i d o x i l a t e was s t u d i e d on rat's h e a r t in acute d e e p h y p o x i a (isolated h e a r t p e r f u s e d - L a n g e n d o r f f t e c h n i q u e - d u r i n g one hour
I N F L U E N C E OF E L E C T R I C A L L Y I N D U C E D AND A C O N I T I N E I N D U C E D A R R H Y T H M I A S ON THE P R O S T A G L A N D I N (PG) E F F L U X OF C O R O N A R Y SINUS B L O O D IN DOGS. H.-J. Mest, Ch. Taube, W. F S r s t e r , D e p a r t m e n t of P h a r m a c o logy, M a r t i n - L u t h e r - U n i v e r s i t y , H a l l e / S a a l e , GDR. The PG e f f l u x in the c a n i n e c o r o n a r y sinus b l o o d was e s t i m a t e d r a d i o i m m u n o l o g i c a l l y after e l e c t r i c a l ly i n d u c e d t a c h y a r r h y t h m i a s and e x t r a s y s t o l e s and after a c o n i t i n e i n d u c e d a r r h y t h m i a s , r e s p e c t i v e l y . T a c h y a r r h y t h m i a s w i t h an i n c r e a s e in f r e q u e n c y of 53% p r o d u c e d an i n c r e a s e of PGE in c o r o n a r y sinus b l o o d of 61% (p<0.01) and of PGF2~ of 67% (p<0.05). A f t e r e x t r a s y s t o l e s there was an i n c r e a s e of the e f f l u x of PGE of 28% (p<0.05) and of PGF~ of i4% (n.s.). The PG e f f l u x in c o r o n a r y sinus ~ o o d was nearly unchanged after aconitine without arrhythmia. However, the PG e f f l u x was i n c r e a s e d a f t e r a r r h y t h m i a had o c c u r r e d , e s p e c i a l l y after v e n t r i c u l a r t a c h y a r r h y t h m i a , v e n t r i c u l a r t a c h y c a r d i a and v e n t r i c u l a r flutter. The e f f l u x of PGE was r a i s e d m o r e than t e n f o l d and of PGF2e m o r e than twofold. The e n h a n c e m e n t of the PG e f f l u x after e x p e r i m e n t a l l y i n d u c e d a r r h y t h m i a s s u g g e s t s a feed b a c k m e c h a n i s m of PGs a g a i n s t a r r h y t h m i c i n f l u e n c e s .
51.
I D E N T I F I C A T I O N OF P R E S U M P T I V E M E S S E N G E R R N A F O R THE H E A V Y C H A I N OF C A R D I A C MYOSIN. J.M. Moalic, P. Padieu, G r o u p e de R e c h e r c h e : D i f f ~ r e n c i a tion B i o c h i m i q u e et C a n c ~ r o g ~ n ~ s e de C e l l u l e s E u c a ryotes en culture. F a c u l t ~ de M ~ d e c i n e , 21033 Dijon, France. T e r m i n a l c a r d i a c d i f f e r e n t i a t i o n of p r e s u m p t i v e m y o b l a s t s is a s s o c i a t e d w i t h the e x p r e s s i o n of n e w b i o s y n t h e t i c p r o g r a m m e s for s p e c i f i c m R N A t r a n s l a tion and e l a b o r a t i o n of the c o n t r a c t i l e a p p a r a t u s . C u l t u r e s of b e a t i n g h e a r t cells f r o m n e w b o r n rat p r o v i d e d a m o d e l for the s t u d y of t r a n s c r i p t i o n of c y t o p l a s m i c RNA and d e t e r m i n a t i o n of m e s s e n g e r R N A e x p r e s s i o n in r e l a t i o n to cell c y c l e and c u l t u r e development. S e p a r a t i o n and i d e n t i f i c a t i o n of c y t o p l ~ s m i c R N A h a v e b e e n c a r r i e d out by a c o m b i n a t i o n of O H - u r i d i n e p u l s e labeling, RNA e x t r a c t i o n , s e d i m e n t a t i o n grad i e n t f r a c t i o n a t i o n and h y b r i d i z a t i o n of p o l y ( A ) c o n t a i n i n g RNA to p o l y u r i d i l i c a c i d d e p o s i t e d on fiber glass filters.
32 R e s u l t s show that h e a r t cells r e a c h i n g c o n f l u e n c y at day-3 in c u l t u r e s y n t h e s i z e s e v e r a l p o l y ( A ) - m R N A species. A m o n g t h e m is a c o n s p i c u o u s peak of poly(A)m R N A which, f r o m its w e l l - d e f i n e d l o c a t i o n b e t w e e n 18S and 28S r i b o s o m a l RNA, can be i d e n t i f i e d as the m e s s e n g e r RNA for the h e a v y c h a i n of cardiac myosin.
52.
A L T E R A T I O N S OF THE P O S T A N O X I C R E C O V E R Y OF THE I N T R A C E L L U L A R R E D O X STATE AS O B S E R V E D IN E A R L Y STAGES OF RAT HEART H Y P E R T R O P H Y . J. Moravec, M. Laplace, G. Renault, U n i t ~ de R e c h e r c h e s de P a t h o l o g i e C a r d i o v a s c u l a i r e , I N S E R M U2, H6pital L ~ o n Bernard, 94450 L i m e i l - B r ~ v a n n e s , France. The c a p a c i t y of i s o l a t e d p e r f u s e d h e a r t s (Langendorff preparation) to o x i d i z e an e x c e s s of N A D H has b e e n t e s t e d by m e a n s of s u r f a c e f l u o r i m e t r y (365 and 470 nm). The k i n e t i c s of the state 5 - t o - s t a t e 3 t r a n s i t i o n has b e e n m o n i t o r e d 2 or 8 days after the b a n d i n g of the aorta and the r e s u l t s c o m p a r e d w i t h those o b t a i n e d on h e a l t h y p r e p a r a t i o n s . The m o s t imp o r t a n t d a t a are the following: (i) the a m p l i t u d e of the signal (PdN r e d u c t i o n ) , as o b s e r v e d 1 min of the anoxic p e r f u s i o n , is c o m p a r a b l e in all groups examined. It equals to 186, 185 and 170% of the a e r o b i c steady state signal in controls, 2 days and 8 daysl a s t i n g stenoses; (2) the time n e c e s s a r y to reach n o r m o x i c r e d o x c o n d i t i o n s is 38.5, 28.5 and 59.25 sec in the three groups e x a m i n e d ; (3) the c o r r e s p o n d i n g m a x i m a l rates of the r e o x i d a t i o n (% of a n o x i c signal/sec) are the following: 3.71, 6.58 and 2.81 per cent/sec. T h e s e r e s u l t s s u g g e s t there is, in h y p e r t r o p h i e d m y o c a r d i u m , a t r a n s i e n t p e r i o d of i m p r o v e d r e s p i r a tory activity, f o l l o w e d by an i m p a i r m e n t of m i t o c h o n d r i a l function. The s i g n i f i c a n c e of the above d a t a for the e t i o l o g y of c o n t r a c t i l e failure w i l l be discussed.
53.
P R O T E C T I V E E F F E C T OF P I R I D O X I L A T E ON H Y P O X I C HEART. P.R. Moret, U. Lutzen, C a r d i a c M e t a b o l i s m L a b o r a t o r y , C e n t e r of C a r d i o l o g y , Geneva, Switzerland. The p r o t e c t i v e a c t i o n of p i r i d o x i l a t e was s t u d i e d on rat's h e a r t in acute d e e p h y p o x i a (isolated h e a r t p e r f u s e d - L a n g e n d o r f f t e c h n i q u e - d u r i n g one hour