[Monsynaptic influences from the reticular formation and muscle afferents following axotomy of motor neurons in rats].
Lumbar motoneurons were studied by means of intracellular recording in intact rats and after section of the appropriate ventral roots. In normal motoneurons monosynaptic EPSPs evoked by stimulation of the reticular formation and Ia group muscle afferents showed no difference in amplitude (3.92 +/- 0.17 mV and 3.86 +/- 0.19 mV), but revealed statistically significant difference in time-to-peak (0.71 +/- 0.05 msec and 0.83 +/- 0.06 msec). The membrane potential, the duration and the amplitude of the actionpotentials, and the generation of antidromic actionpotentials showed no difference between normal and axotomized motoneurons. The partial responses were not recorded in axotomized motoneurons. Monosynaptic reticulo-spinal and Ia EPSPs of axotomized motoneurons exhibited longer time-to-peak than those in normal motoneurons. Besides, Ia EPSPs were significantly reduced in amplitude. The changes of monosynaptic reticulo-spinal and Ia EPSPs cannot be explained exclusively by the alterations of the synapses located on the soma and proximal dendrites.
D000818:Animals; D008564:Membrane Potentials; D009046:Motor Neurons / Q000502:physiology*; D009132:Muscles / Q000294:innervation*; D009410:Nerve Degeneration; D009475:Neurons, Afferent / Q000502:physiology; D051381:Rats; D012154:Reticular Formation / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology*; D013570:Synaptic Membranes / Q000502:physiology
Monosinapticheskie vliianiia iz retikuliarnoĭ formatsii i myshechnykh afferentov posle aksotomii motoneĭronov krysy.