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Protective effect of adenosine on anoxic damage of hippocampal slices
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7. Cell death P R O T E C T I V E E F F E C T OF A D E N O S I N E O N A N O X I C D A M A G E O F H I P P O C A M P A I S L I C E S . M A S A H I R O MORI, T O M O Y U K I N I S H I Z A K I A N D Y A S U H I R O OKADA, D e p a r t m e n t of P h y s i o l o g y , K o b e U n i v e r s i t y S c h o o l of M e d i c i n e , 7 - 5 - 1 K u s u n o k i - c h o , C h u o - k u , K o b e 650, Japan. To i n v e s t i g a t e the e f f e c t of a d e n o s i n e (AD) on a n o x i c d a m a g e of b r a i n tissue, e n e r g y m e t a b o l i s m in r e l a t i o n to n e u r a l a c t i v i t y was s t u d i e d u s i n g h i p p o c a m p a l s l i c e s f r o m the g u i n e a pig. The c o n c e n t r a t i o n s of A T P and C r P in e a c h s l i c e was d e t e r m i n e d and a l s o p o s t s y n a p t i c p o t e n t i a l s (PSP, p o p u l a t i o n spike) w e r e r e c o r d e d in the g r a n u l a r c e l l l a y e r of the s l i c e s . I n c u b a t i o n of s l i c e s w i t h A D (5 mM) for 120 m i n i n c r e a s e d the A T P l e v e l in the s l i c e f r o m 10.2 to 19.7 m m o l / k g p r o t e i n . D u r i n g d e p r i v a t i o n of b o t h o x y g e n (02) and g l u c o s e , AD d i d not a l t e r the r a t e of c o n s u m p t i o n of h i g h e n e r g y p h o s p h a t e s . H o w e v e r , p r e t r e a t m e n t of s l i c e s w i t h A D (5 mM) c o n s i d e r a b l y e n h a n c e d the r e c o v e r y of the A T P l e v e l d u r i n g r e o x y g e n a t i o n w i t h g l u c o s e a f t e r d e p r i v a t i o n of 09 and g l u c o s e . PSP w e r e r e c o r d e d b e f o r e d e p r i v a t i o n of 09 and g l u c o s e , or d ~ p r i v a t i o n of g l u c o s e only, and a f t e r the d e p r i v a t i o n and f o l l o w i n g r e o x y g e n a t i o n w i t h g l u c o s e in the c o n t r o l s l i c e s a n d the s l i c e s p r e t r e a t e d w i t h A D (5 mM) for 60 min. A D p r o l o n g e d the s u r v i v a l time of t i s s u e s l i c e s by 5 to 10 m i n in c a s e of d e p r i v a t i o n of 02 and g l u c o s e a n d by a b o u t 60 m i n in c a s e of d e p r i v a t i o n of g l u c o s e only. Thus the f u n c t i o n a l r e c o v e r y of PSP a g r e e d w e l l w i t h the r e s u l t s of the r e c o v e r y of the A T P l e v e l in the s l i c e s t r e a t e d w i t h AD. AD has a p r o t e c t i v e e f f e c t on b r a i n t i s s u e a g a i n s t a n o x i c d a m a g e by e n h a n c i n g the t i s s u e A T P l e v e l d u r i n g the r e c o v e r y p e r i o d .
TIlE VARIATION OF EXTRACELLULAB DOPAMINE AND GLUTAMATE IN TIlE STRIATUM FOLLOWING THE OCCLUSION OF TIlE MIDDLE CEREBRAl. ARTERY IN TIlE RAT. TAKESHI }tASHITAN1L KAZUO KOIDE~, NOBUKAZU HASHINOT~*, SATOStll t l A [ ' f O t l ~=. TERU~J SAKURAI ~, XIREX ZXOU~ AKIRA MITANI a KIYOSHI KATAOKA4 , IIAZIME NAGAI x , AND HITO0 NIS!IINO. Dci,artments -f Physiology, :NeurosurKer~ and 2Orthopedics, X:~I;()Y~, C i t y U n i v e r ~ i tY Medical S c h 0 0 1 , M i z u h o - c h 0 , M i z u b R T k o , N a g o y a 467, and ~ D e p a [ t m c n t of p h Y S i g ( o z Y , E h i m e Univel[sity~ SchooJ el 5Jedicine, O n s e n - ~ u D , E h i m e 7 9 1 c Q 2 , Japan. To c l a r i f y the m e c h a n i s m of i s c h e m i c n e u r o n a l cell d e a t h in the s t r i a t u m with respect to neurotransmitters, the right middle cerebral artery (MCA) was selectively occluded for 60 m i n i n t h e r a t and extracellular dopamine and glutamate levels in the striatum were measured using microdialysis. The occlusion induced isehemic neuronal cell death in the lateral part of the striatum and neighborin~ cortex. Unilateral turnin~ and hemiple~ia were observed in these animals. In the passive avoidance test, learnin~ ability was impaired. The content of extracellular dopamine in(ueased markedly ( 8 0 to 320 times) during the occlusion (peak, a t 20 a n d 40 min after occlusion), and returned It) t h e b a s a l level 2 houFs after occlusion. DOPAC a n d /IVA decreased. The content of glutamate also increased, but the time courses were different from those of dopamine. These results suggest that the marked release of dopamine as well as glutamate is involved in neuronal cell death in the stiatum following ischemia.
MATURE SYMPATHETIC NEURONS DO NOT DIE, BUT UNDERGO DEGENERATION IN RESPONSE TO ACUTE WITHDRAWAL OF NERVE GROWTH FACTOR IN VITRO: MECHANISM OF CELLULAR SHRINKAGE. TATSURO KOIKE, Department of Natural Science, Sasa Hedical School, Nabeshima, Sasa 849. Sympathetic neurons dissociated from new-born rats were grown for I week in the presence of nerve growth factor (NGF). These young neurons died in response to acute deprivation of NGF. In contrast, NGF withdrawal did not cause cell death of mature neurons grown for more than 3 weeks in vitro. We have previously proposed a Ca2+ set-point hypothesis for the degree of neuronal dependence on trophic factor for survival. This hypothesis predicts that young neurons whose intraeellular Ca2+ level is low, require trophlc factor for survival, while mature neurons whose cytoplasmic Ca2+ level is high, may survive independent of trophic support. Indeed, fura-2 measurements revealed that cytoplasmic Ca2+ level was higher in mature neurons (200-240nM) than in young neurons (80-100nM). These mature neurons, however, undergo degeneration in response to withdrawal of EGF: degeneration consisted of three-independent processes including cellular shrinkage. Cell shrinkage occurred slowly upon deprivation of NGF and was reversible. By measuring cell diameter using a computer-assisted video-analysis system~ we found that either ouabain (I ~M) or low-Na+ (
7. Cell death P R O T E C T I V E E F F E C T OF A D E N O S I N E O N A N O X I C D A M A G E O F H I P P O C A M P A I S L I C E S . M A S A H I R O MORI, T O M O Y U K I N I S H I Z A K I A N D Y A S U H I R O OKADA, D e p a r t m e n t of P h y s i o l o g y , K o b e U n i v e r s i t y S c h o o l of M e d i c i n e , 7 - 5 - 1 K u s u n o k i - c h o , C h u o - k u , K o b e 650, Japan. To i n v e s t i g a t e the e f f e c t of a d e n o s i n e (AD) on a n o x i c d a m a g e of b r a i n tissue, e n e r g y m e t a b o l i s m in r e l a t i o n to n e u r a l a c t i v i t y was s t u d i e d u s i n g h i p p o c a m p a l s l i c e s f r o m the g u i n e a pig. The c o n c e n t r a t i o n s of A T P and C r P in e a c h s l i c e was d e t e r m i n e d and a l s o p o s t s y n a p t i c p o t e n t i a l s (PSP, p o p u l a t i o n spike) w e r e r e c o r d e d in the g r a n u l a r c e l l l a y e r of the s l i c e s . I n c u b a t i o n of s l i c e s w i t h A D (5 mM) for 120 m i n i n c r e a s e d the A T P l e v e l in the s l i c e f r o m 10.2 to 19.7 m m o l / k g p r o t e i n . D u r i n g d e p r i v a t i o n of b o t h o x y g e n (02) and g l u c o s e , AD d i d not a l t e r the r a t e of c o n s u m p t i o n of h i g h e n e r g y p h o s p h a t e s . H o w e v e r , p r e t r e a t m e n t of s l i c e s w i t h A D (5 mM) c o n s i d e r a b l y e n h a n c e d the r e c o v e r y of the A T P l e v e l d u r i n g r e o x y g e n a t i o n w i t h g l u c o s e a f t e r d e p r i v a t i o n of 09 and g l u c o s e . PSP w e r e r e c o r d e d b e f o r e d e p r i v a t i o n of 09 and g l u c o s e , or d ~ p r i v a t i o n of g l u c o s e only, and a f t e r the d e p r i v a t i o n and f o l l o w i n g r e o x y g e n a t i o n w i t h g l u c o s e in the c o n t r o l s l i c e s a n d the s l i c e s p r e t r e a t e d w i t h A D (5 mM) for 60 min. A D p r o l o n g e d the s u r v i v a l time of t i s s u e s l i c e s by 5 to 10 m i n in c a s e of d e p r i v a t i o n of 02 and g l u c o s e a n d by a b o u t 60 m i n in c a s e of d e p r i v a t i o n of g l u c o s e only. Thus the f u n c t i o n a l r e c o v e r y of PSP a g r e e d w e l l w i t h the r e s u l t s of the r e c o v e r y of the A T P l e v e l in the s l i c e s t r e a t e d w i t h AD. AD has a p r o t e c t i v e e f f e c t on b r a i n t i s s u e a g a i n s t a n o x i c d a m a g e by e n h a n c i n g the t i s s u e A T P l e v e l d u r i n g the r e c o v e r y p e r i o d .
TIlE VARIATION OF EXTRACELLULAB DOPAMINE AND GLUTAMATE IN TIlE STRIATUM FOLLOWING THE OCCLUSION OF TIlE MIDDLE CEREBRAl. ARTERY IN TIlE RAT. TAKESHI }tASHITAN1L KAZUO KOIDE~, NOBUKAZU HASHINOT~*, SATOStll t l A [ ' f O t l ~=. TERU~J SAKURAI ~, XIREX ZXOU~ AKIRA MITANI a KIYOSHI KATAOKA4 , IIAZIME NAGAI x , AND HITO0 NIS!IINO. Dci,artments -f Physiology, :NeurosurKer~ and 2Orthopedics, X:~I;()Y~, C i t y U n i v e r ~ i tY Medical S c h 0 0 1 , M i z u h o - c h 0 , M i z u b R T k o , N a g o y a 467, and ~ D e p a [ t m c n t of p h Y S i g ( o z Y , E h i m e Univel[sity~ SchooJ el 5Jedicine, O n s e n - ~ u D , E h i m e 7 9 1 c Q 2 , Japan. To c l a r i f y the m e c h a n i s m of i s c h e m i c n e u r o n a l cell d e a t h in the s t r i a t u m with respect to neurotransmitters, the right middle cerebral artery (MCA) was selectively occluded for 60 m i n i n t h e r a t and extracellular dopamine and glutamate levels in the striatum were measured using microdialysis. The occlusion induced isehemic neuronal cell death in the lateral part of the striatum and neighborin~ cortex. Unilateral turnin~ and hemiple~ia were observed in these animals. In the passive avoidance test, learnin~ ability was impaired. The content of extracellular dopamine in(ueased markedly ( 8 0 to 320 times) during the occlusion (peak, a t 20 a n d 40 min after occlusion), and returned It) t h e b a s a l level 2 houFs after occlusion. DOPAC a n d /IVA decreased. The content of glutamate also increased, but the time courses were different from those of dopamine. These results suggest that the marked release of dopamine as well as glutamate is involved in neuronal cell death in the stiatum following ischemia.
MATURE SYMPATHETIC NEURONS DO NOT DIE, BUT UNDERGO DEGENERATION IN RESPONSE TO ACUTE WITHDRAWAL OF NERVE GROWTH FACTOR IN VITRO: MECHANISM OF CELLULAR SHRINKAGE. TATSURO KOIKE, Department of Natural Science, Sasa Hedical School, Nabeshima, Sasa 849. Sympathetic neurons dissociated from new-born rats were grown for I week in the presence of nerve growth factor (NGF). These young neurons died in response to acute deprivation of NGF. In contrast, NGF withdrawal did not cause cell death of mature neurons grown for more than 3 weeks in vitro. We have previously proposed a Ca2+ set-point hypothesis for the degree of neuronal dependence on trophic factor for survival. This hypothesis predicts that young neurons whose intraeellular Ca2+ level is low, require trophlc factor for survival, while mature neurons whose cytoplasmic Ca2+ level is high, may survive independent of trophic support. Indeed, fura-2 measurements revealed that cytoplasmic Ca2+ level was higher in mature neurons (200-240nM) than in young neurons (80-100nM). These mature neurons, however, undergo degeneration in response to withdrawal of EGF: degeneration consisted of three-independent processes including cellular shrinkage. Cell shrinkage occurred slowly upon deprivation of NGF and was reversible. By measuring cell diameter using a computer-assisted video-analysis system~ we found that either ouabain (I ~M) or low-Na+ (