ISSN:
1432-1106
Keywords:
Monosynaptic response
;
Primary afferent depolarization
;
Spinal cord
;
Cat
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Long trains of electrical stimuli supramaximal for Group I fibers of PBST nerves were used to study the effect on GS pathway. Inhibition of GS monosynaptic response occurred during PBST stimulation: however, decline in the inhibition developed with time despite the constancy of the inhibitory input monitored from the dorsal root. The level of recovery of the monosynaptic reflex at steady state depended upon the frequency of PBST stimulation, the higher the frequency the more complete the recovery. The effect of increasing the frequency of GS stimulation was to increase the inhibitory effect from PBST. Enhanced excitability of GS primary afferent endings in monosynaptic contact with homonymous motoneurons occurred and decreased parallel to the recovery of the monosynaptic response. When present, the polysynaptic response evoked by stimulating GS peripheral nerves increased during PBST stimulation in an inverse relation to changes in the monosynaptic response. Intracellular recordings from GS motoneurons usually revealed no change in membrane potential or in excitability of postsynaptic membrane to direct stimulation. Increased delay of intracellular GS spike potential was observed during PBST stimulation. The amount of this shift can be accounted for by polysynaptic activation of the same motoneuron.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00234312
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