scholarly journals Early postnatal development of GABAergic presynaptic inhibition of Ia proprioceptive afferent connections in mouse spinal cord

2013 ◽  
Vol 109 (8) ◽  
pp. 2118-2128 ◽  
Author(s):  
Patrick M. Sonner ◽  
David R. Ladle
Keyword(s):  
Spinal Cord ◽  
Postnatal Development ◽  
Presynaptic Inhibition ◽  
Dorsal Root ◽  
Reciprocal Inhibition ◽  
Afferent Feedback ◽  
Early Postnatal Development ◽  
Ia Afferent ◽  
Ia Afferents ◽  
Stimulation Of

Sensory feedback is critical for normal locomotion and adaptation to external perturbations during movement. Feedback provided by group Ia afferents influences motor output both directly through monosynaptic connections and indirectly through spinal interneuronal circuits. For example, the circuit responsible for reciprocal inhibition, which acts to prevent co-contraction of antagonist flexor and extensor muscles, is driven by Ia afferent feedback. Additionally, circuits mediating presynaptic inhibition can limit Ia afferent synaptic transmission onto central neuronal targets in a task-specific manner. These circuits can also be activated by stimulation of proprioceptive afferents. Rodent locomotion rapidly matures during postnatal development; therefore, we assayed the functional status of reciprocal and presynaptic inhibitory circuits of mice at birth and compared responses with observations made after 1 wk of postnatal development. Using extracellular physiological techniques from isolated and hemisected spinal cord preparations, we demonstrate that Ia afferent-evoked reciprocal inhibition is as effective at blocking antagonist motor neuron activation at birth as at 1 wk postnatally. In contrast, at birth conditioning stimulation of muscle nerve afferents failed to evoke presynaptic inhibition sufficient to block functional transmission at synapses between Ia afferents and motor neurons, even though dorsal root potentials could be evoked by stimulating the neighboring dorsal root. Presynaptic inhibition at this synapse was readily observed, however, at the end of the first postnatal week. These results indicate Ia afferent feedback from the periphery to central spinal circuits is only weakly gated at birth, which may provide enhanced sensitivity to peripheral feedback during early postnatal experiences.

Effect of percutaneous electrical stimulation of the spinal cord on the manifestation of reciprocal and presynaptic inhibition α-motor neurons of the lower leg muscles against the background of a weak isometric contraction in magnitude

2021 ◽  
Author(s):  
D.A. Gladchenko ◽  
S.M. Bogdanov ◽  
L.V. Roshchina ◽  
A.A. Chelnokov
Keyword(s):  
Spinal Cord ◽  
Electrical Stimulation ◽  
Motor Neurons ◽  
Isometric Contraction ◽  
Presynaptic Inhibition ◽  
Plantar Flexion ◽  
Reciprocal Inhibition ◽  
Non Invasive ◽  
Leg Muscles ◽  
Stimulation Of

The article presents the results of a study of the reflex mechanisms of reciprocal and presynaptic inhibition at rest and when performing an isometric reduction of 5% of MPS against the background of twenty-minute non-invasive electrical stimulation of the spinal cord. It was found that at rest against the background of electrical stimulation, reciprocal and presynaptic inhibition was inverted to their relief, and when performing plantar flexion of the foot, on the contrary, reciprocal and presynaptic inhibition increased, but the severity of presynaptic inhibition was greater. Key words: percutaneous electrical stimulation of the spinal cord, reciprocal inhibition, presynaptic inhibition, isometric contraction.

Modulation of monosynaptic excitation in the neonatal rat spinal cord

1993 ◽  
Vol 70 (3) ◽  
pp. 1151-1158 ◽  
Author(s):  
M. Pinco ◽  
A. Lev-Tov
Keyword(s):  
Spinal Cord ◽  
Dorsal Root ◽  
Neonatal Rat ◽  
Bathing Solution ◽  
Duration Stimulus ◽  
Low Calcium ◽  
Dorsal Root Afferents ◽  
Stimulation Of ◽  
Monosynaptic Excitation

1. The effects of high-frequency (5-50 Hz) stimulation of dorsal root afferents on monosynaptic excitation of alpha motoneurons was studied in the in vitro spinal cord preparation of the neonatal rat, using sharp-electrode intracellular recordings. 2. Double pulse stimulation of dorsal root afferents induced severe depression of testing excitatory postsynaptic potentials (EPSPs) at each of the tested interstimulus intervals (15 ms-5 s). After perfusion of the preparation with low-calcium, high-magnesium Krebs saline, the amplitude of the conditioning EPSPs was markedly decreased and the testing EPSPs exhibited substantial facilitation that was maximal at the 20-ms interval and that was accompanied by depression at intervals > or = 60-100 ms. 3. Short-duration stimulus trains applied to dorsal root afferents normally induced tetanic depression of the intracellularly recorded monosynaptic EPSPs. Switching the bathing solution to low-calcium, high-magnesium saline decreased the control EPSP and induced facilitation and then tetanic potentiation (TP) of the EPSPs within the applied train. The magnitude of potentiation (% potentiation) of these EPSPs depended on the interpulse interval of the short stimulus train and on the degree of attenuation of the unpotentiated control EPSP after the solution was changed from normal- to low-calcium Krebs solution. 4. Long-duration stimulus trains applied to dorsal root afferents at 5-10 Hz induced marked depression of monosynaptic EPSPs during the train. The depression was alleviated after cessation of the tetanic stimulation and was followed in some cases by slight posttetanic potentiation.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Expression Profile of Long Non-Coding RNAs during Early Postnatal Development of Mouse Spinal Cord

2020 ◽  
Vol 6 (2) ◽  
pp. 18 ◽  
Author(s):  
Bert Verheijen
Keyword(s):  
Spinal Cord ◽  
Postnatal Development ◽  
Expression Profile ◽  
Editorial Office ◽  
Early Postnatal Development ◽  
Mouse Spinal Cord ◽  
The Public ◽  
Non Coding Rna ◽  
Public Record ◽  
Non Coding Rnas

Out of respect for the institution’s wishes, in agreement with the Non-Coding RNA Editorial Office, and in agreement with the author, this article has been removed from the public record and marked as retracted. Please refer to the retraction note.

Effects of tetanic stimulation on monosynaptic and dorsal root reflexes in kittens

1991 ◽  
Vol 69 (10) ◽  
pp. 1428-1435
Author(s):  
Parveen Bawa
Keyword(s):  
Spinal Cord ◽  
Dorsal Root ◽  
Monosynaptic Reflex ◽  
Cutaneous Afferents ◽  
Tetanic Stimulation ◽  
Dorsal Root Reflex ◽  
Peripheral Afferents ◽  
Post Tetanic Potentiation ◽  
Tetanic Depression ◽  
Stimulation Of

The effects of tetanic stimulation of peripheral afferents were examined on monosynaptic reflexes and dorsal root reflexes in kittens of various ages. Concomitantly recorded monosynaptic and dorsal root reflexes resulting from the stimulation of muscle nerves showed similar post-tetanic changes, namely, predominantly post-tetanic depression in neonates and post-tetanic potentiation in older kittens or adults. However, the changes in post-tetanic responses expressed as a percentage of control in dorsal root reflexes were much smaller than those in monosynaptic reflexes. When dorsal root reflexes originating from muscle and cutaneous afferents were compared, dorsal root reflexes from the latter behaved quite differently. For all ages, post-tetanic effects on dorsal root reflexes arising from cutaneous afferents were either insignificant or very small. The possible mechanisms underlying differences in post-tetanic effects from muscle and cutaneous afferents in adults and neonates are discussed.Key words: cat, kitten, development, dorsal root reflex, monosynaptic reflex, spinal cord, post-tetanic potentiation.

scholarly journals Repeated and patterned stimulation of cutaneous reflex pathways amplifies spinal cord excitability

2020 ◽  
Vol 124 (2) ◽  
pp. 342-351 ◽  
Author(s):  
Gregory E. P. Pearcey ◽  
E. Paul Zehr
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
Presynaptic Inhibition ◽  
Sensory Stimulation ◽  
Cutaneous Afferents ◽  
Reflex Excitability ◽  
Cutaneous Reflex ◽  
Reflex Pathways ◽  
Muscle Reflex ◽  
Stimulation Of

Priming via patterned stimulation of the nervous system induces neuroplasticity. Yet, accessing previously known cutaneous reflex pathways to alter muscle reflex excitability has not yet been examined. Here, we show that sensory stimulation of the cutaneous afferents that innervate the foot sole can amplify spinal cord excitability, which, in this case, is attributed to reductions in presynaptic inhibition.

Functional differences between afferent fibers in the hypogastric and pelvic nerves innervating female reproductive organs in the rat

1993 ◽  
Vol 69 (2) ◽  
pp. 533-544 ◽  
Author(s):  
K. J. Berkley ◽  
A. Robbins ◽  
Y. Sato
Keyword(s):  
Spinal Cord ◽  
Dorsal Root ◽  
Reproductive Tract ◽  
Nerve Fibers ◽  
Pelvic Nerve ◽  
Hypogastric Nerve ◽  
Afferent Fibers ◽  
Pelvic Nerves ◽  
Different Parts ◽  
Stimulation Of

1. The uterus, cervix, and vaginal canal are innervated by afferent fibers in the hypogastric and pelvic nerves. Four studies compared the innervation territory and sensitivity to peripheral stimuli of the two sets of fibers in adult virgin rats. 2. Innervation territory was studied anatomically by injecting different fluorescent dyes into different parts of the reproductive, lower urinary, and lower digestive tracts and examining retrogradely labeled neurons in dorsal root ganglia. It was also studied electrophysiologically in anesthetized rats by summing potentials evoked in branches of the two nerves by electrical stimulation of different parts of the reproductive tract. 3. In both studies sensory innervation of the reproductive tract shifted from the pelvic to the hypogastric nerve (i.e., shifted entry into the spinal cord from the L6-S1 to the T13-L3 dorsal root ganglia, respectively) as the dye or stimulating electrode shifted from the vaginal entrance to the uterine horns, with fibers from both nerves densely innervating the cervix region (i.e., entering the spinal cord through both sets of ganglia). The anatomic results suggested that the regions innervated by fibers in one nerve might also be innervated by a small component of normally quiescent fibers in the other nerve. 4. Response sensitivity was studied electrophysiologically by simultaneously recording multiunit activity in branches of the hypogastric and pelvic nerves in two ways. First, in intact, anesthetized rats, activity was recorded during mechanical stimulation of the reproductive tract (distension of the vagina and uterus, probing the cervix). Second, in an in vitro organ preparation of the uterus and vagina, activity was recorded during chemical stimulation through the uterine artery with bradykinin, serotonin, NaCN, CO2, and KCl. 5. Pelvic nerve fibers were markedly more sensitive than hypogastric nerve fibers to uterine and cervical mechanostimulation. Similarly, pelvic nerve fibers were more likely to respond or responded more vigorously than hypogastric nerve fibers to all chemical stimuli (except KCl). 6. These results provide strong evidence that afferent fibers in the pelvic and hypogastric nerves of nulliparous adult rats subserve different functions in reproduction and sensation. Pelvic nerve fibers seem closely tied to sensory and behavioral processes associated with mating and conception, whereas hypogastric fibers seem closely tied to pregnancy and nociception, with fibers in both nerves serving functions during parturition.

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