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2208 Magnetic evoked field from the CA1 hippocampal slice of the guinea pig
S236
2206 Shionogi
AN E L E C T R O C H E M I C A L D E T E C T I O N OF NO IN RAT BRAIN BY D I E F E R E N T I A L PULSE VOLTAMMETRY. M A S A T O IKEDA R e s e a r c h Lab. r Shionogi & Co. r Ltd. t Toyonaka t Osaka 561 r Japan
To detect the NO release in the brain, d i f f e r e n t i a l pulse v o l t a m m e t r y using an e l e c t r o c h e m i c a l l y treated carbon fiber electrode (7 Hm diameter) was developed. A carbon fiber electrode combined with a cannula being used for m i c r o - i n f u s i o n tests was inserted into the rat cerebellum. A linear r e l a t i o n s h i p between current and NO c o n c e n t r a t i o n was o b s e r v e d (slope, 3.0 nA per 1 Hbl). The o x i d a t i o n peak potential (+930 mVl obtained from the c e r e b e l l u m c o r r e s p o n d e d to the in v i t r o potential of NO solution. P r o g r e s s i v e decrease in peak height was o b s e r v e d after m i c r o - i n f u s i o n of N ~ - n i t r o - L - a r g i n i n e (i Hg/0.5 ~i). N ~ - n i t r o - L - a r g i n i n e antagonized N M D A - i n d u c e d increase in peak height. H e m o g l o b i n (i0 -3 M/0.5 HI) a l s o produced the r e d u c t i o n of peak height and completely inhibited the e l e v a t i o n of peak height induced by NMDA. I o n o m y c i n (0.i ~g/0.5 ~i) and W-7 (i ~g/0.5 ul) caused the e l e v a t i o n and r e d u c t i o n of peak height, .respectively. These results indicate that the major c o n t r i b u t o r to o x i d a t i o n peak at 930 mV observed in c e r e b e l l u m might be NO. This technique is useful for m o n i t o r i n g the e n d o g e n o u s NO release in the brain.
2207 MASAHIKO
DEVELOPMENT OBSERVATION HIRANO,
OF OF RYOKO
A FIBER-OPTIC CEREBELLAR TSUBOKAWA
PLATE TISSUES AND ATSUO
Department of Phototechnology, Photon Medical Research Center, Medicine, Handa-eho, Hamamatsu, 431-31, Japan
MICROSCOPE
AND
MIYAKAWA,
Hamamatsu University School of
A new-type video microscope system employing a fiber-optic plate was developed. The fiber-optic plate used here was processed in the shape of a needle 50mm in length and Imm in diameter. This fiber-optic pl~te consists of approximately I00,000 optical fibers 3/~m in diameter. This fiber-optic plate was set in front of an objective lens to face a specimen. An image at an area adjacent to the end of the fiber-optic plate is transmitted to the objective. The image was then detected with a video camera and digitized for storage in an image processor. By inserting the fiber-optic plate, it is expected that internal tissues of an animal can be observed at the single cell level in real time. Using this system, cerebellar slices of a rat were observed. The slices were stained with a fluorescent dye so as to discriminate between the layer of cell bodies and that of processes easily. In the observation of the layer of cell bodies, each cell could be visualized and the image was distinctly discriminated from that of the layer of processes. These observations show that the fiber-optic plate microscope system has the sufficient spatial resolution for detecting a single cell in the tissue and discriminating the layered structure of a cerebellum.
2208
MAGNETIC EVOKED FIELD FROM THE CA1 HIPPOCAMPAL SLICE OF THE GUINEA PIG. SHIN-ICHI KYUHOU1,2 AND YOSHIO OKADA 2, 1Dept of Integrative Physiol., Natl lnst. for Physiol. Sci., Myodaiii, Okazaki 444, lapan and 2Det~ts. Neurol. & Physiol., Univ. New Mexico, Albuquerque, New Mexico, NM87131, U.S.A Magnetic evoked fields (MEFs) of the guinea pig h i p p o c a m p a l slice were recorded by using a high resolution m a g n e t o m e t e r . We'prepared the guinea pig transverse slice containing only CA1 region by a s t a n d a r d procedure. The longitudinal axis of pyramidal cells is arranged parallel each o t h e r in this r e d u c e d slice; thus the cellular c u r r e n t s responsible for the MEFs could be easily d e d u c e d . The slice was placed on a nylon n e t resting on a plastic pedestal a n d immersed in oxygenated Ringer solution containing O.05"mM picrotoxin. Evoked responses were i n d u c e d by electrical stimulation (50 ps, 1-3 mA) to the s t r a t u m radiatum. Marked MEFs (1-6 pT) could be observed with latency of 2.5-3.5 ms. The spatial p a t t e r n of the MEFs showed that it was ~lue to the longitudinal current~ of the pyramidal cells. Bath application of kynurenic acid extinguished m o s t of the sigmils. This indicates that the d o m i n a n t contribution of postsynaptic currents to the MEFs.
2206 Shionogi
AN E L E C T R O C H E M I C A L D E T E C T I O N OF NO IN RAT BRAIN BY D I E F E R E N T I A L PULSE VOLTAMMETRY. M A S A T O IKEDA R e s e a r c h Lab. r Shionogi & Co. r Ltd. t Toyonaka t Osaka 561 r Japan
To detect the NO release in the brain, d i f f e r e n t i a l pulse v o l t a m m e t r y using an e l e c t r o c h e m i c a l l y treated carbon fiber electrode (7 Hm diameter) was developed. A carbon fiber electrode combined with a cannula being used for m i c r o - i n f u s i o n tests was inserted into the rat cerebellum. A linear r e l a t i o n s h i p between current and NO c o n c e n t r a t i o n was o b s e r v e d (slope, 3.0 nA per 1 Hbl). The o x i d a t i o n peak potential (+930 mVl obtained from the c e r e b e l l u m c o r r e s p o n d e d to the in v i t r o potential of NO solution. P r o g r e s s i v e decrease in peak height was o b s e r v e d after m i c r o - i n f u s i o n of N ~ - n i t r o - L - a r g i n i n e (i Hg/0.5 ~i). N ~ - n i t r o - L - a r g i n i n e antagonized N M D A - i n d u c e d increase in peak height. H e m o g l o b i n (i0 -3 M/0.5 HI) a l s o produced the r e d u c t i o n of peak height and completely inhibited the e l e v a t i o n of peak height induced by NMDA. I o n o m y c i n (0.i ~g/0.5 ~i) and W-7 (i ~g/0.5 ul) caused the e l e v a t i o n and r e d u c t i o n of peak height, .respectively. These results indicate that the major c o n t r i b u t o r to o x i d a t i o n peak at 930 mV observed in c e r e b e l l u m might be NO. This technique is useful for m o n i t o r i n g the e n d o g e n o u s NO release in the brain.
2207 MASAHIKO
DEVELOPMENT OBSERVATION HIRANO,
OF OF RYOKO
A FIBER-OPTIC CEREBELLAR TSUBOKAWA
PLATE TISSUES AND ATSUO
Department of Phototechnology, Photon Medical Research Center, Medicine, Handa-eho, Hamamatsu, 431-31, Japan
MICROSCOPE
AND
MIYAKAWA,
Hamamatsu University School of
A new-type video microscope system employing a fiber-optic plate was developed. The fiber-optic plate used here was processed in the shape of a needle 50mm in length and Imm in diameter. This fiber-optic pl~te consists of approximately I00,000 optical fibers 3/~m in diameter. This fiber-optic plate was set in front of an objective lens to face a specimen. An image at an area adjacent to the end of the fiber-optic plate is transmitted to the objective. The image was then detected with a video camera and digitized for storage in an image processor. By inserting the fiber-optic plate, it is expected that internal tissues of an animal can be observed at the single cell level in real time. Using this system, cerebellar slices of a rat were observed. The slices were stained with a fluorescent dye so as to discriminate between the layer of cell bodies and that of processes easily. In the observation of the layer of cell bodies, each cell could be visualized and the image was distinctly discriminated from that of the layer of processes. These observations show that the fiber-optic plate microscope system has the sufficient spatial resolution for detecting a single cell in the tissue and discriminating the layered structure of a cerebellum.
2208
MAGNETIC EVOKED FIELD FROM THE CA1 HIPPOCAMPAL SLICE OF THE GUINEA PIG. SHIN-ICHI KYUHOU1,2 AND YOSHIO OKADA 2, 1Dept of Integrative Physiol., Natl lnst. for Physiol. Sci., Myodaiii, Okazaki 444, lapan and 2Det~ts. Neurol. & Physiol., Univ. New Mexico, Albuquerque, New Mexico, NM87131, U.S.A Magnetic evoked fields (MEFs) of the guinea pig h i p p o c a m p a l slice were recorded by using a high resolution m a g n e t o m e t e r . We'prepared the guinea pig transverse slice containing only CA1 region by a s t a n d a r d procedure. The longitudinal axis of pyramidal cells is arranged parallel each o t h e r in this r e d u c e d slice; thus the cellular c u r r e n t s responsible for the MEFs could be easily d e d u c e d . The slice was placed on a nylon n e t resting on a plastic pedestal a n d immersed in oxygenated Ringer solution containing O.05"mM picrotoxin. Evoked responses were i n d u c e d by electrical stimulation (50 ps, 1-3 mA) to the s t r a t u m radiatum. Marked MEFs (1-6 pT) could be observed with latency of 2.5-3.5 ms. The spatial p a t t e r n of the MEFs showed that it was ~lue to the longitudinal current~ of the pyramidal cells. Bath application of kynurenic acid extinguished m o s t of the sigmils. This indicates that the d o m i n a n t contribution of postsynaptic currents to the MEFs.