Recovery of forelimb voluntary movement following reinnervation of forelimb muscles by respiratory nerve in the cat

S129 RECOVERY OF FORELIMB VOLUNTARY MOVEMENT FOLLOWING REINNERVATION OF FORELIMB MUSCLES BY RESPIRATORY NERVE IN THE CAT YUTAKA FUJITO*, HIROSHI KAWASAKI* and MAMORU AOKI, Department of Physiology, Sapporo Medical College, S.I, W.17, Chuo-ku, Sapporo 060, Japan. We examined whether cats can compensate movement disorders when once-denervated arm muscles are supplied by a respiratory nerve. Right phrenic and musculocutaneus nerves were cut for cross union and the proximal stump of the phrenic nerve was united to the peripheral stump of the museulocutaneus nerve. Tendons of elbow flexors innervated by nerves other than the musculocutaneus nerve (M. cleidobrachialis and M. brachioradialis) were cut to maximize use of the cross-innervated muscles. Animals were anaesthetized with pentobarbital sodium (35 mg/kg, ip) in all surgical procedures. Rhythmic electromiographic (EMG) activities and contractions appeared synchronized with the inspiratory phase 7 to 9 weeks after the cross un~on. Reinnervation of arm muscles by the phrenic nerve was also examined histologically by retrogradely labeled phrenic motoneurons following injection of HRP to the M. biceps brachii. EMG recordings from arm muscles and video recording of arm movements were simultaneusly conducted to analyse behaviors of the cross-innervated forelimb. Teflon coated stainless steel wires were fixed in the right M. biceps brachii and M. triceps brachii, and their outlet connector was attached to the skull with dental cement in order to record EMG from freely moving cats. During stereotyped movement such as locomotion, EMG activities of the right M. biceps brachii did not syncronize with walking cycles. In contrast, during voluntary goal directed movements, cats could reach their r~ght forepaw to goals smoothly with elbow flexion which was associated with EMG activities of the M. biceps brachii~ indicating functional compensation of forelimb movement disorders by the nervous system for voluntary control of respiration.

~N ANALYSIS OF T H E RINTHECTOMIZED CAT USING THE

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MINORU ~DA, MAKOTO MIYAOKA*ana E T S U R O ITO~ D e 2 a r t m e n t of N e u r o s u r g e r y and Casualty Center, Juntenao UniversIzunagaoka Hospital, Izunagaoka, Shizuoka-ken, 41U-22, JAPAN

Quantitative measurement of local cerebral glucose utilizat i o n (LCGU, S o k o l o f f et al, 1977) w a s p e r f o r m e d in t h e u n a n e s t h e tized nemilabyrinthectomized cat during uncompensated and compensated stages. Hemilabyrinthectomy was first carried out at 2 hours, z4 h o u r s , 4 w e e k s o r i0 m o n t h s p r i o r to t h e m e a s u r e m e n t of L C G U . T h e r a t e s of L C G U a r e e x p r e s s e d as p e r c e n t a g e s of t h e c o n t r o l value. [I] U n c o m p e n s a t e d animals : L C G U in t h e d e a f f e r e n t e d vestib u l a r n u c l e u s is w e l l b e l o w ( 62% o f t h e c o n t r o l v a l u e ) t h a t o n t h e i n t a c t s i d e (101%). T h e i n c r e a s e d L C G U c a n be s e e n in N u c l . reticularis parvocellularis (125%), N u c l p o n t i s (150%) o n b o t h sides and ipsilateral a b d u c e n s n u c l e u s a n d its v e n t r a l p a r t ( as m u c h as 2 1 2 % ) . T h e p o s t e r i o r v e r m i s ( 150~200% ) and the nodulofloccular (214%) a r e v e r y a c t i v e . [Z] C o m p e n s a t e d animals ; T h e L C G U in t h e d e a f f e r e n t e d vestibular n u c l . h a s i n c r e a s e d so as to e q u a l t h a t o f t h e i n t a c t ( 90~i00% ) . T h e i n c r e a s e a L C G U c a n be s e e n in t h e N u c l . r e t i c u l a r i s parvocellularis, gigantocellularis and lateralis (120~160%). L C G U in the i n f e r i o r o l i v e is a l m o s t e q u a l to t h e c o n t r o l v a l u e . The posterior vermis and the cerebellar nuclei are very active ( 160%, 1 3 0 ~ 150% ) . These results suggest that the mechanism and structures necessary for the compensation most likely reside within the brain stem and cerebellum. However, visual and spinal inputs are also suggested to b e i n v o l v e d .