Summary
In precollicular decerebrate cats repetitive stimulation of the lateral vestibular nucleus causes acceleration of the discharge of primary and secondary endings of muscle spindles of the ipsilateral gastrocnemius muscle. The spindle excitation outlasts the stimulus and the extrafusal contraction. This long-lasting effect is abolished by barbiturates leaving only an initial excitation which runs parallel with muscle tension record. While this effect is indicative of the depressant action exerted directly or indirectly by barbiturates on spinal internuncials transmitting vestibular excitation to fusimotor neurones, the persistent initial excitation suggests the existence of a more direct pathway from Deiters' nucleus to fusimotor neurones. This pathway is probably monosynaptic as that described for α motoneurones by Lund and Pompeiano.
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References
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This investigation was supported by PHS research grant NB 05695-02 from the National Institute of Neurological Diseases and Blindness, N.I.H., Public Health Service, U.S.A.
Fellow of IBRO/Unesco. Present address: Department of Physiological Sciences, University of Lagos Medical School, Lagos, Nigeria.
Fellow of the Ministero della Pubblica Istruzione.
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Pompeiano, O., Diete-Spiff, K. & Carli, G. Two pathways transmitting vestibulospinal influences from the lateral vestibular nucleus of Deiters to extensor fusimotor neurones. Pflugers Arch. 293, 272–275 (1967). https://doi.org/10.1007/BF00417124
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DOI: https://doi.org/10.1007/BF00417124