Presynaptic inhibition of the monosynaptic reflex by vibration

Abstract

SUMMARYIn cats, the monosynaptic reflex (MSR) elicited from L 7 or S1 dorsal roots, or from the tibial nerve (H reflex) was suppressed by vibration at 50-500 c/s of the hind limb with innervation intact. The MSR was not suppressed by selective vibration of cutaneous receptors, and suppression was still observed after the hind limb was skinned. In contrast, the phenomenon disappeared when all muscle nerves were crushed.Suppression of the MSR by vibration was shown to be mediated by presynaptic inhibition by the following methods: correlation with onset of the dorsal root potential (DRP) evoked by vibration, and abolition of both DRP and reflex suppression by picrotoxin; demonstration of primary afferent depolarization and normal excitability of motoneurones to direct stimulation.Reasons are given for deducing that the muscle afferent fibres responsible for the presynaptic inhibition induced by vibration are group Ia rather than groups Ib or II, or afferent fibres from Pacinian corpuscles.

Effect of Bone Tissue on Vibration-Induced Electrical Activity of Muscles

“…42,43 Gil li es et al showed that the H-ref lex was not sup pres sed by the se lec ti ve vib ra ti on of cu ta ne o us re cep tors, and that this sup pres si on was still ob ser ved af ter the hind limb was skin ned in cats. 36 Cody et al and Martin et al al so sho wed that the vib ra ti on of cu ta ne o us re cep tors did not ca u se any sig ni fi cant ef fect on the ref lex res pon se. 18,20 Jo int re cep tor af fe rents of ten res pond in both di rec ti ons (e.g.…”

“…It is im pro bab le that se con dary spind le en dings and Gol gi ten don or gans play any part in H-ref lex suppres si on. 35,36,39,44 BO NE MEC HA NO RE CEP TORS AND AF FE RENTS An in cre a se in musc le elec tri cal ac ti vity at rest indi ca tes an in cre a se in mo tor ne u ron po ol ac ti va tion. 25,37 In the pre sent study, it was fo und that the re was an in cre a se in EMG ac ti vity at rest du ring vib ra ti on, and that the UD ra di us BMC might ha ve had an ef fect on this in cre a se.…”

“…Se ve ral stu di es ha ve shown that the vib ra ti on sup pres ses the H-ref lex amp li tu de. 27,[35][36][37] In the pre sent study, FCR H ref lex was fo und to be sup pres sed or depres sed du ring vib ra ti on, as well. H-ref lex sup pressi on/dep res si on ca u sed by vib ra ti on is exp la i ned by presy nap tic in hi bi ti on of musc le spind le gro up Ia af fe rents.…”

Influences of H and Medium Latency Reflex Responses of the Soleus Muscle while Receiving with Malleolus Vibration during Upright Standing

“…The major finding of previous studies is that vibratory stimulation can be used to reduce the excitation of α motoneurons. This theoretical background indicates that vibratory stimulation applied to the muscle spindle provokes a decrease in the excitation of monosynaptic and oligosynaptic reflexes, resulting in presynaptic inhibition of group I and II afferent fibers [20][21][22] . We postulate that the inhibition of group I and group II afferents from the ankle joint is possible by applying vibration from the cutaneous to the ankle joint.…”

The Effects of Radius Bone Density on the Resting Myoelectrical Activity of Contralateral Wrist Flexors in Subjects Exposed to Unilateral Forearm Vibration

“…7 On the contrary, it was shown that the vibration treatment did not enhance the muscle spindle sensitivity and led to presynaptic inhibition of muscle spindle group Ia afferents. [8][9][10][11] As an alternative to tonic vibration reflex, recently described bone myoregulation reflex has been suggested to explain the increased muscle strength and electrical activity induced by vibration. Through the bone myoregulation reflex, bone is sensitive to mechanical stimuli and can send mechanical input signals to central nervous system, resulting in neuronal stimulation of muscle activity.…”