- Email: [email protected]
Effects of long term β-adrenoceptor blockade
34 d e v e l o p e d to cardiac failure, w h e r e a s glucose p r o t e c t i v e effect on the cardiac function.
has a
55.
EFFECTS OF LONG TERM B - A D R E N O C E P T O R BLOCKADE. W.G. Nayler, C.E. Yepez, A.M. Slade, E. Fassold, C a r d i o t h o r a c i c Institute, U n i v e r s i t y of London, England. Young male rabbits (52-54 days) injected s.c. for 5-7 weeks with dl p r o p r a n o l o l (i m g / k g / 1 2 hrs) showed a normal h e a r t / b o d y w e i g h t ratio and normal cardiac u l t r a s t r u c t u r e . D o s e - r e s p o n s e curves for the p o s i t i v e inotropic effect of i s o p r e n a l i n e indicated that e f f e c t i v e B - a d r e n o c e p t o r b l o c k a d e was absent more than 12 hrs after giving the last dose of propranolol. A similar result was o b t a i n e d with respect to the ability of p r o p r a n o l o l to p r e v e n t h y p o x i a from causing a raised resting tension. That some effects of l o n g - t e r m 8-blockade r e m a i n e d less than 48 hrs after the last dose of p r o p r a n o l o l had been given became evident w h e n these hearts were made hypoxic and the s u b s e q u e n t release of CPK and change in m i t o c h o n d r i a l function was quantitated. This work was supported by a grant from the M e d i c a l R e s e a r c h Council.
M Y O C A R D I A L C Y T O S O L I C c A M P - D E P E N D E N T PROTEIN KINASES. V E N T R I C U L A R D I S T R I B U T I O N AND EFFECT OF T R I I O D O T H Y R O N I N E INDUCED HYPERTROPHY. M. Newcomb, K. Gibson, P. Harris, C a r d i o t h o r a c i c Institute, Univ e r s i t y of London, England. We have studied the a c t i v i t y of c A M P - d e p e n d e n t p r o t e i n kinases in v e n t r i c u l a r cytosol and the effect of t r i i o d o t h y r o n i n e induced h y p e r t r o p h y on their activity. Both the basal a c t i v i t y and that s t i m u l a t e d by c A ~ w e r e higher in the left v e n t r i c l e than the right v e n t r i c l e of 200 g rats (p<.02 and p<.001 respectively). Daily i n t r a p e r i t o n e a l injection of 15.6 ~g/100 g body w e i g h t T 3 to 200 g rats caused an increase in the ratios of left and right v e n t r i c u l a r w e i g h t s to body w e i g h t at 3 days (p<.005), w h i c h then r e m a i n e d stable up to 7 days. The basal and total cytosolic p r o t e i n kinase activity was i n c r e a s e d in both v e n t r i c l e s at 3 days (p<.001) and d e c l i n e d to normal by 7 days. The protein kinase a c t i v i t y thus seemed to be linked to the 56.
has a
55.
EFFECTS OF LONG TERM B - A D R E N O C E P T O R BLOCKADE. W.G. Nayler, C.E. Yepez, A.M. Slade, E. Fassold, C a r d i o t h o r a c i c Institute, U n i v e r s i t y of London, England. Young male rabbits (52-54 days) injected s.c. for 5-7 weeks with dl p r o p r a n o l o l (i m g / k g / 1 2 hrs) showed a normal h e a r t / b o d y w e i g h t ratio and normal cardiac u l t r a s t r u c t u r e . D o s e - r e s p o n s e curves for the p o s i t i v e inotropic effect of i s o p r e n a l i n e indicated that e f f e c t i v e B - a d r e n o c e p t o r b l o c k a d e was absent more than 12 hrs after giving the last dose of propranolol. A similar result was o b t a i n e d with respect to the ability of p r o p r a n o l o l to p r e v e n t h y p o x i a from causing a raised resting tension. That some effects of l o n g - t e r m 8-blockade r e m a i n e d less than 48 hrs after the last dose of p r o p r a n o l o l had been given became evident w h e n these hearts were made hypoxic and the s u b s e q u e n t release of CPK and change in m i t o c h o n d r i a l function was quantitated. This work was supported by a grant from the M e d i c a l R e s e a r c h Council.
M Y O C A R D I A L C Y T O S O L I C c A M P - D E P E N D E N T PROTEIN KINASES. V E N T R I C U L A R D I S T R I B U T I O N AND EFFECT OF T R I I O D O T H Y R O N I N E INDUCED HYPERTROPHY. M. Newcomb, K. Gibson, P. Harris, C a r d i o t h o r a c i c Institute, Univ e r s i t y of London, England. We have studied the a c t i v i t y of c A M P - d e p e n d e n t p r o t e i n kinases in v e n t r i c u l a r cytosol and the effect of t r i i o d o t h y r o n i n e induced h y p e r t r o p h y on their activity. Both the basal a c t i v i t y and that s t i m u l a t e d by c A ~ w e r e higher in the left v e n t r i c l e than the right v e n t r i c l e of 200 g rats (p<.02 and p<.001 respectively). Daily i n t r a p e r i t o n e a l injection of 15.6 ~g/100 g body w e i g h t T 3 to 200 g rats caused an increase in the ratios of left and right v e n t r i c u l a r w e i g h t s to body w e i g h t at 3 days (p<.005), w h i c h then r e m a i n e d stable up to 7 days. The basal and total cytosolic p r o t e i n kinase activity was i n c r e a s e d in both v e n t r i c l e s at 3 days (p<.001) and d e c l i n e d to normal by 7 days. The protein kinase a c t i v i t y thus seemed to be linked to the 56.