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Ascending and descending projections of the nucleus reticularis magnocellularis of the medulla oblongata in cats: An anterograde axonal tracing study using phaseolus vulgaris leucoagglutinin
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EFFECTS OF BETHANECHOL INJECTION INTO PONTINE RETICULAR FORMATION UPON POSTURAL CHANGES ACCOMPANYING A FOOD RETRIEVINGTASK BY A FORELIMB IN A STANDING CAT TAKASHI SAKAMOTO~ YVES GAHERY*AND SHIGEMI MORI~ Department of Physiology, Asahikawa Medical College 7 Asahikawa, Hokkaido~ 078 JAPAN, *Laboratoire de Neurosciences Fonctionnelles, C.N.R.S.~ 13402 Marseille CEDEX 9, FRANCE Cats were trained to maintain a quiet standing posture on four force transducers, and they were conditioned to lift the left or right forelimb and retrieve food from a beaker with a forepaw, which was placed in front of the animal. For focal microinjection of bethanechol (2-4 ug/O.25pl), a stainless steel cannula (outer diameter of 300pm) was inserted into the target area (P3.0, L or R2.0 to 2.5, H-3.0 to 4.0) through a chronically-implanted guide tube. Within a few minutes after injection of bethanechol, the cat became less attentive. Although the cat tried to lift a forelimb and reach the beaker, it could not perform the desired forelimb movement as quickly as before injection and often failed to retrieve food. During this period, the position of the head gradually went down with passive flexion of bilateral forelimbs, and body sway of the cat increased. Reflecting those behavioral changes, the maximum decreasing rate of vertical force became smaller and the amplitude of fluctuation of the center of the pressure became larger than that before injection. Several minutes after the injection, the cat could no longer lift a forelimb and reach the beaker. It could not maintain a standing posture anymore and tended to sit down. After i0 to 20 minutes, the cat could not even keep a sitting posture and, finally, it lay down. These results suggest that the pontine reticular formation plays a major role in controling postural adjustment accompanying a voluntary movement. ASCENDING AND DESCENDING PROJECTIONS OF THE NUCLEUS RETICULARIS MAGNOCELLULARIS OF THE MEDULLA OBLONGATA IN CATS: AN ANTEROGRADE AXONAL TRACING STUDY USING PHASEOLUS VULGARIS LEUCOAGGLUTININ. YOSHIHIRO OHTA I , KIYOJI MATSUYAMA .2, SHIGEMI MORI I , AND HIROSHI KIMURA 3, IDepartment of Physiology, 2 Department of Physiology~ Yamagata University I Yamagata Asahikawa Medical College I Asahikawa 0781 990-231 3Molecular Neurobiology Center I Shiga Medical College, Ootsu 520-21 t Japan. Efferent projections of the nucleus reticularis magnocellularis (Me) of the medulla oblongata were studied using a specific anterograde tracer, Phaseolus vulgaris leucoagglutinin (PHA-L) in cats. PEA-L-labeled fibers descended into the ventral and lateral funiculi of the cervical cord bilaterally from the medial part of the Me, but exited from its lateral part exclusively ipsilaterally. Labeled terminals were distributed in laminae IV-X, mainly in laminae VII, VIII, and IX in the cervical cord. They were also found in the lateral column at the thoracic level, in the intermediolateral column, and Onuf's nucleus at the sacral level. Reconstruction of a single labeled axon entering from the lateral funiculus into lamina IX showed that the axon bifurcated several times to make terminal boutons which appeared to contact directly with somata of motoneurons. In the diencephalon, terminals were found bilaterally in thalamic nuclei, the dorsal and lateral hypothalamic areas, nucl. of the fields of Forel, and nucl. of zona incerta. In the brainstem, they were scattered in the mesencephalic, pontine, and medullary reticular formation. They were also located in the red nucl., substantia nigra, raphe nuclei, locus coeruleus complex, and periaqueductal gray. Remarkably dense terminals were found in the oculomotor nucl. and the dorsal motor nucl. of vagus. These results suggest that the Mc plays an important role in motor control, sensory processing, autonomic regulation, and their integration.
40. Sleep and biological rhythms A ROLE OF PROSTAGLANDIN E2 IN P H Y S I O L O G I C A L SLEEP-WAKEFULNESS p REGULATION. HITOSHI M A T S U M U R A I , KAZUKI H O N D A *z , W A N S U N G CHO1.3 , S H O J I R O I N Q U E *~ , T O S H I A K I S A K A 1 . 4 , A N D O S A M U H A Y A I S H I I, i O s a k a B i o s c i e n c e Institute, 6-2-4 Furuedai, Suita, O s a k a 565, J a p a n , 2Institute f o r M e d i c a l and Dental Engineering. T o k y o M e d i c a l and D e n t a l U n i v e r s i t v , 2 - 3 - 1 0 K a n d a - S u r u ~ a d a i , Chivoda-ku, Tokyo 101, Japan, SDepartment o_ff A n a t o m y , ColleKe o__ff M e d i c i n e , Gyeon~-San~ National University, C h i l a m - D o n K 92, ChinJu. K y o n ~ N a m 6 6 0 - 2 8 0 , Korea, and 4 D e p a r t m e n t off Neuropsychiatry, Osaka Medical ColleKe, 2-7 DaiKaku-cho, Takatsuki, O s a k a 569, Japan. We previously reported that prostaglandin E2 (PGE2) a d m i n i s t e r e d into the b r a i n of rats i n c r e a s e s the time that the animal spends in w a k e f u l n e s s . This a w a k i n g e f f e c t of PGE2 w a s f u r t h e r e x a m i n e d b y continuous i n f u s i o n s of PGE2 a n d / o r A H 6809, an antagonist of a s u b t y p e o f PGE2 receptor, into the t h i r d v e n t r i c l e of f r e e l y m o v i n g rats. C h a n g e s in b r a i n t e m p e r a t u r e w e r e also r e c o r d e d b e c a u s e PGE2 is k n o w n to c a u s e h y p e r t h e r m i a . A H 6 8 0 9 (21 p m o l / m i n ) p l u s PGE2 (10 pmol/min) blocked an augmentation of wakefulness and did not inhibit h y p e r t h e r m i a , w h e r e a s PGE2 a l o n e i n d u c e d a u g m e n t a t i o n of wakefulness and hyperthermia. A n i n f u s i o n of A H 8 8 0 9 (21 p m o l / m i n ) alone r e d u c e d w a k e f u l n e s s w i t h o u t a f f e c t i n E b r a i n temperature. T h e s e r e s u l t s s t r o n g l y suEgest that endoEenous PGE2 p h y s i o l o g i c a l l y acts to m a i n t a i n and a u g m e n t w a k e f u l n e s s and t h a t t h e m e c h a n i s m is i n d e p e n d e n t of P G E 2 - m e d i a t e d hyperthermia.
EFFECTS OF BETHANECHOL INJECTION INTO PONTINE RETICULAR FORMATION UPON POSTURAL CHANGES ACCOMPANYING A FOOD RETRIEVINGTASK BY A FORELIMB IN A STANDING CAT TAKASHI SAKAMOTO~ YVES GAHERY*AND SHIGEMI MORI~ Department of Physiology, Asahikawa Medical College 7 Asahikawa, Hokkaido~ 078 JAPAN, *Laboratoire de Neurosciences Fonctionnelles, C.N.R.S.~ 13402 Marseille CEDEX 9, FRANCE Cats were trained to maintain a quiet standing posture on four force transducers, and they were conditioned to lift the left or right forelimb and retrieve food from a beaker with a forepaw, which was placed in front of the animal. For focal microinjection of bethanechol (2-4 ug/O.25pl), a stainless steel cannula (outer diameter of 300pm) was inserted into the target area (P3.0, L or R2.0 to 2.5, H-3.0 to 4.0) through a chronically-implanted guide tube. Within a few minutes after injection of bethanechol, the cat became less attentive. Although the cat tried to lift a forelimb and reach the beaker, it could not perform the desired forelimb movement as quickly as before injection and often failed to retrieve food. During this period, the position of the head gradually went down with passive flexion of bilateral forelimbs, and body sway of the cat increased. Reflecting those behavioral changes, the maximum decreasing rate of vertical force became smaller and the amplitude of fluctuation of the center of the pressure became larger than that before injection. Several minutes after the injection, the cat could no longer lift a forelimb and reach the beaker. It could not maintain a standing posture anymore and tended to sit down. After i0 to 20 minutes, the cat could not even keep a sitting posture and, finally, it lay down. These results suggest that the pontine reticular formation plays a major role in controling postural adjustment accompanying a voluntary movement. ASCENDING AND DESCENDING PROJECTIONS OF THE NUCLEUS RETICULARIS MAGNOCELLULARIS OF THE MEDULLA OBLONGATA IN CATS: AN ANTEROGRADE AXONAL TRACING STUDY USING PHASEOLUS VULGARIS LEUCOAGGLUTININ. YOSHIHIRO OHTA I , KIYOJI MATSUYAMA .2, SHIGEMI MORI I , AND HIROSHI KIMURA 3, IDepartment of Physiology, 2 Department of Physiology~ Yamagata University I Yamagata Asahikawa Medical College I Asahikawa 0781 990-231 3Molecular Neurobiology Center I Shiga Medical College, Ootsu 520-21 t Japan. Efferent projections of the nucleus reticularis magnocellularis (Me) of the medulla oblongata were studied using a specific anterograde tracer, Phaseolus vulgaris leucoagglutinin (PHA-L) in cats. PEA-L-labeled fibers descended into the ventral and lateral funiculi of the cervical cord bilaterally from the medial part of the Me, but exited from its lateral part exclusively ipsilaterally. Labeled terminals were distributed in laminae IV-X, mainly in laminae VII, VIII, and IX in the cervical cord. They were also found in the lateral column at the thoracic level, in the intermediolateral column, and Onuf's nucleus at the sacral level. Reconstruction of a single labeled axon entering from the lateral funiculus into lamina IX showed that the axon bifurcated several times to make terminal boutons which appeared to contact directly with somata of motoneurons. In the diencephalon, terminals were found bilaterally in thalamic nuclei, the dorsal and lateral hypothalamic areas, nucl. of the fields of Forel, and nucl. of zona incerta. In the brainstem, they were scattered in the mesencephalic, pontine, and medullary reticular formation. They were also located in the red nucl., substantia nigra, raphe nuclei, locus coeruleus complex, and periaqueductal gray. Remarkably dense terminals were found in the oculomotor nucl. and the dorsal motor nucl. of vagus. These results suggest that the Mc plays an important role in motor control, sensory processing, autonomic regulation, and their integration.
40. Sleep and biological rhythms A ROLE OF PROSTAGLANDIN E2 IN P H Y S I O L O G I C A L SLEEP-WAKEFULNESS p REGULATION. HITOSHI M A T S U M U R A I , KAZUKI H O N D A *z , W A N S U N G CHO1.3 , S H O J I R O I N Q U E *~ , T O S H I A K I S A K A 1 . 4 , A N D O S A M U H A Y A I S H I I, i O s a k a B i o s c i e n c e Institute, 6-2-4 Furuedai, Suita, O s a k a 565, J a p a n , 2Institute f o r M e d i c a l and Dental Engineering. T o k y o M e d i c a l and D e n t a l U n i v e r s i t v , 2 - 3 - 1 0 K a n d a - S u r u ~ a d a i , Chivoda-ku, Tokyo 101, Japan, SDepartment o_ff A n a t o m y , ColleKe o__ff M e d i c i n e , Gyeon~-San~ National University, C h i l a m - D o n K 92, ChinJu. K y o n ~ N a m 6 6 0 - 2 8 0 , Korea, and 4 D e p a r t m e n t off Neuropsychiatry, Osaka Medical ColleKe, 2-7 DaiKaku-cho, Takatsuki, O s a k a 569, Japan. We previously reported that prostaglandin E2 (PGE2) a d m i n i s t e r e d into the b r a i n of rats i n c r e a s e s the time that the animal spends in w a k e f u l n e s s . This a w a k i n g e f f e c t of PGE2 w a s f u r t h e r e x a m i n e d b y continuous i n f u s i o n s of PGE2 a n d / o r A H 6809, an antagonist of a s u b t y p e o f PGE2 receptor, into the t h i r d v e n t r i c l e of f r e e l y m o v i n g rats. C h a n g e s in b r a i n t e m p e r a t u r e w e r e also r e c o r d e d b e c a u s e PGE2 is k n o w n to c a u s e h y p e r t h e r m i a . A H 6 8 0 9 (21 p m o l / m i n ) p l u s PGE2 (10 pmol/min) blocked an augmentation of wakefulness and did not inhibit h y p e r t h e r m i a , w h e r e a s PGE2 a l o n e i n d u c e d a u g m e n t a t i o n of wakefulness and hyperthermia. A n i n f u s i o n of A H 8 8 0 9 (21 p m o l / m i n ) alone r e d u c e d w a k e f u l n e s s w i t h o u t a f f e c t i n E b r a i n temperature. T h e s e r e s u l t s s t r o n g l y suEgest that endoEenous PGE2 p h y s i o l o g i c a l l y acts to m a i n t a i n and a u g m e n t w a k e f u l n e s s and t h a t t h e m e c h a n i s m is i n d e p e n d e n t of P G E 2 - m e d i a t e d hyperthermia.