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Neural activity and energy metabolism in guinea pig and frog brain slices
S83 NEURAL
ACTIVITY
AND
ENERGY
METABOLISM
IN
GUINEA
PIG
AND
FROG
BRAIN
SLICES
YASUHIRO OKADA, KAZUSHI YONEDA, MICHINORI TANIMOTO*, TOMOYUKI NISHIZAKI*, TOSHIO ARAKAWA*, TAKAAKI MIYAMOTO* and RYOHEI YAMAUCHI*. Dept. Physiology, Sch. Med., Kobe University, Kusunoki-cho, Chuo-ku, Kobe 650, Japan Thin brain slices (300 um thick) were prepared from the hippocampus of t h e guinea pig and the olfactoYy lobe and tectum of t h e f r o g ( R a n a c a t e s p i a n a ) . Summer frogs were used for the experiment. In t h e g u i n e a pig hippocampal slices, the granular c e l l l a y e r of d e n t a t e gyrus was stimulated and the postsynaptic field potential (PSP) was recorded from the CA 3 a region of t h e p y r a m i d a l cell layer. In the frog brain slices, stimulation was appIied to t h e o l f a c t o r y lobe and tectum and PSP was recorded from the adjacent a r e a of t h e s t i m u l a t i n g electrode. The neural activity and energy u s e r a t e of t h e s l i c e s w e r e s t u d i e d during the warming and cooling of t h e m e d i u m , and during anoxia. Temperature and PSP amplitude: In t h e h i p p o c a m p a l slices, cooling the medium from 3 7 ° C to 2 0 ° C c a u s e d a decrease of t h e P S P a m p l i t u d e , although the amplitude increased (120%) transiently at a b o u t 3 3 ° C . The neural activity ceased at 2 1 ° C . Raising the temperature f r o m 2 1 ° C to 3 7 ° C , t h e a c t i v i t y recovered reversibly. However raising the temperature over 38°C, the amplitude decreased, and disappeared irreversibly at 4 2 ° C . In t h e f r o g s l i c e s , the PSP amplitude was highest at 2 6 28°C. Cooling the medium, it w a s r e d u c e d a n d l o s t at I O - 1 1 ° C r e v e r s i b l y ; and on warming at o v e r 2 8 ° C it w a s r e d u c e d and abolished irreversibly at 3 7 ° C . Effect of a n o x i a : In h i p p o c a m p a l slices, PSP amplitude decreased very rapidly during anoxia (O~ a n d g l u c o s e deprivation) and was abolished in 6 m i n at 3 6 ° C , b u t in 16 m i n at 2 8 ° C . In f r o g b r a i n s l i c e , a n o x i a caused a slow reduction in t h e P S P amplitude and abolished it in 6 0 - 7 0 m i n at 2 8 ° C a n d 9 0 - 1 1 0 m i n at 2 0 ° C . Enersy use rate: Energy use rate in the hippocampal slices was calculated by the Np consumption which was measured from the reduction of A T P a n d c r e a t i n e - P and the increase of l a c t a t e during the initial p h a s e of a n o x i a . The up use rate was 42.2 mmol/kg protein/min at 3 7 ° C , 2 2 . 8 at 2 8 ° C a n d 7 . 0 at 2 1 ° C . In f r o g b r a i n s l i c e s , the rate was measured by oxygen consumption. The oxygen consumption was 6.93 mmol O2/kg protein/min at 3 7 ° C , 2 . 3 2 at 2 8 ° C a n d 0 . 7 0 at 2 0 ° C , r e s p e c t i v e l y .
COLUMNAR ORGANIZATION IN THE SUBICULUM FORMED BY THE AXON BRANCHES ORIGINATING FROM THE HIPPOCAMPAL CA1 PYRAMIDAL NEURONS IN THE RAT: THEIR ORDER AND RELATIONSHIP WITH HIPPOCAMPAL FORMATION NOBUAKI TAMAMAKI AND YOSHIAKI NOJYO, Department of Anatomy, 910-11 Japan
Fukui Medical School, Matsuoka,
Fukui
Intracellular HRP study combined with the immunoperoxidase technique was carried out on the hippocampal CA1 pyramidal neurons. Male albino SD rats were anesthetized with pentobarbital (50 mg/kg, i.p.) and fixed in a stereotaxic apparatus. The CA1 pyramidal neurons on the plane 2.5 mm lateral to the median plane in the left hemisphere were labeled by pressure-injection of HRP followed by PAP immunohistochemistry. The pyramidal neurons were reconstructed and analyzed in three dimensions with the aid of a computer system. In the six well stained pyramidal neurons, five had a rostrally directed axon branch, which penetrated into the lateral septum in two cases. All six pyramidal neurons had numerous caudally directed axon branches, which terminated in the subiculum or proceeded to the entorhinal cortex. The axon branches in the subiculum bifurcated repeatedly and formed a slub-like terminal arborization (250-300 zm wide, 500-550 ~m high, 1.8-2.2 mm long). The width of the arborization seemed to fit in with the diameter of the columnar dendritic field and the height to accord with the thickness of the subicular gray matter. The labeled terminal branches in the subiculum distributed from layers I to V of the gray matter, and were rather dense in layers II and III. The CA1 pyramidal neurons located caudally on the plane 2.5 mm lateral to the median plane formed the slub-like terminal arborization in the rostral part of the subiculum. The CA1 pyramidal neurons located rostrally, which will belong to the CAIc region, formed the slub-like arborization in the caudal part of the subiculum near the border between the subiculum and the presubiculum. The CA1 pyramidal neuron located medially, which will belong to the CAIb region, formed the slublike arborization in the medial part of the subiculum. This study indicates that the CA1 pyramidal neurons form columns in the subiculum, with reversed order in the rostro-caudal direction. This order of correspondence was reconfirmed by the anterograde HRP labeling of the CAI pyramidal neurons in each region.
ACTIVITY
AND
ENERGY
METABOLISM
IN
GUINEA
PIG
AND
FROG
BRAIN
SLICES
YASUHIRO OKADA, KAZUSHI YONEDA, MICHINORI TANIMOTO*, TOMOYUKI NISHIZAKI*, TOSHIO ARAKAWA*, TAKAAKI MIYAMOTO* and RYOHEI YAMAUCHI*. Dept. Physiology, Sch. Med., Kobe University, Kusunoki-cho, Chuo-ku, Kobe 650, Japan Thin brain slices (300 um thick) were prepared from the hippocampus of t h e guinea pig and the olfactoYy lobe and tectum of t h e f r o g ( R a n a c a t e s p i a n a ) . Summer frogs were used for the experiment. In t h e g u i n e a pig hippocampal slices, the granular c e l l l a y e r of d e n t a t e gyrus was stimulated and the postsynaptic field potential (PSP) was recorded from the CA 3 a region of t h e p y r a m i d a l cell layer. In the frog brain slices, stimulation was appIied to t h e o l f a c t o r y lobe and tectum and PSP was recorded from the adjacent a r e a of t h e s t i m u l a t i n g electrode. The neural activity and energy u s e r a t e of t h e s l i c e s w e r e s t u d i e d during the warming and cooling of t h e m e d i u m , and during anoxia. Temperature and PSP amplitude: In t h e h i p p o c a m p a l slices, cooling the medium from 3 7 ° C to 2 0 ° C c a u s e d a decrease of t h e P S P a m p l i t u d e , although the amplitude increased (120%) transiently at a b o u t 3 3 ° C . The neural activity ceased at 2 1 ° C . Raising the temperature f r o m 2 1 ° C to 3 7 ° C , t h e a c t i v i t y recovered reversibly. However raising the temperature over 38°C, the amplitude decreased, and disappeared irreversibly at 4 2 ° C . In t h e f r o g s l i c e s , the PSP amplitude was highest at 2 6 28°C. Cooling the medium, it w a s r e d u c e d a n d l o s t at I O - 1 1 ° C r e v e r s i b l y ; and on warming at o v e r 2 8 ° C it w a s r e d u c e d and abolished irreversibly at 3 7 ° C . Effect of a n o x i a : In h i p p o c a m p a l slices, PSP amplitude decreased very rapidly during anoxia (O~ a n d g l u c o s e deprivation) and was abolished in 6 m i n at 3 6 ° C , b u t in 16 m i n at 2 8 ° C . In f r o g b r a i n s l i c e , a n o x i a caused a slow reduction in t h e P S P amplitude and abolished it in 6 0 - 7 0 m i n at 2 8 ° C a n d 9 0 - 1 1 0 m i n at 2 0 ° C . Enersy use rate: Energy use rate in the hippocampal slices was calculated by the Np consumption which was measured from the reduction of A T P a n d c r e a t i n e - P and the increase of l a c t a t e during the initial p h a s e of a n o x i a . The up use rate was 42.2 mmol/kg protein/min at 3 7 ° C , 2 2 . 8 at 2 8 ° C a n d 7 . 0 at 2 1 ° C . In f r o g b r a i n s l i c e s , the rate was measured by oxygen consumption. The oxygen consumption was 6.93 mmol O2/kg protein/min at 3 7 ° C , 2 . 3 2 at 2 8 ° C a n d 0 . 7 0 at 2 0 ° C , r e s p e c t i v e l y .
COLUMNAR ORGANIZATION IN THE SUBICULUM FORMED BY THE AXON BRANCHES ORIGINATING FROM THE HIPPOCAMPAL CA1 PYRAMIDAL NEURONS IN THE RAT: THEIR ORDER AND RELATIONSHIP WITH HIPPOCAMPAL FORMATION NOBUAKI TAMAMAKI AND YOSHIAKI NOJYO, Department of Anatomy, 910-11 Japan
Fukui Medical School, Matsuoka,
Fukui
Intracellular HRP study combined with the immunoperoxidase technique was carried out on the hippocampal CA1 pyramidal neurons. Male albino SD rats were anesthetized with pentobarbital (50 mg/kg, i.p.) and fixed in a stereotaxic apparatus. The CA1 pyramidal neurons on the plane 2.5 mm lateral to the median plane in the left hemisphere were labeled by pressure-injection of HRP followed by PAP immunohistochemistry. The pyramidal neurons were reconstructed and analyzed in three dimensions with the aid of a computer system. In the six well stained pyramidal neurons, five had a rostrally directed axon branch, which penetrated into the lateral septum in two cases. All six pyramidal neurons had numerous caudally directed axon branches, which terminated in the subiculum or proceeded to the entorhinal cortex. The axon branches in the subiculum bifurcated repeatedly and formed a slub-like terminal arborization (250-300 zm wide, 500-550 ~m high, 1.8-2.2 mm long). The width of the arborization seemed to fit in with the diameter of the columnar dendritic field and the height to accord with the thickness of the subicular gray matter. The labeled terminal branches in the subiculum distributed from layers I to V of the gray matter, and were rather dense in layers II and III. The CA1 pyramidal neurons located caudally on the plane 2.5 mm lateral to the median plane formed the slub-like terminal arborization in the rostral part of the subiculum. The CA1 pyramidal neurons located rostrally, which will belong to the CAIc region, formed the slub-like arborization in the caudal part of the subiculum near the border between the subiculum and the presubiculum. The CA1 pyramidal neuron located medially, which will belong to the CAIb region, formed the slublike arborization in the medial part of the subiculum. This study indicates that the CA1 pyramidal neurons form columns in the subiculum, with reversed order in the rostro-caudal direction. This order of correspondence was reconfirmed by the anterograde HRP labeling of the CAI pyramidal neurons in each region.