Recurrent inhibition in the cat's spinal cord

Renshaw recurrent inhibition (RI) plays an important gated role in spinal motion circuit. Peripheral nerve injury is a common disease in clinic. Our current research was designed to investigate the change of the recurrent inhibitory function in the spinal cord after the peripheral nerve crush injury in neonatal rat. Sciatic nerve crush was performed on 5-day-old rat puppies and the recurrent inhibition between lateral gastrocnemius-soleus (LG-S) and medial gastrocnemius (MG) motor pools was assessed by conditioning monosynaptic reflexes (MSR) elicited from the sectioned dorsal roots and recorded either from the LG-S and MG nerves by antidromic stimulation of the synergist muscle nerve. Our results demonstrated that the MSR recorded from both LG-S or MG nerves had larger amplitude and longer latency after neonatal sciatic nerve crush. The RI in both LG-S and MG motoneuron pools was significantly reduced to virtual loss (15–20% of the normal RI size) even after a long recovery period upto 30 weeks after nerve crush. Further, the degree of the RI reduction after tibial nerve crush was much less than that after sciatic nerve crush indicatig that the neuron-muscle disconnection time is vital to the recovery of the spinal neuronal circuit function during reinnervation. In addition, sciatic nerve crush injury did not cause any spinal motor neuron loss but severally damaged peripheral muscle structure and function. In conclusion, our results suggest that peripheral nerve injury during neonatal early development period would cause a more sever spinal cord inhibitory circuit damage, particularly to the Renshaw recurrent inhibition pathway, which might be the target of neuroregeneration therapy.

Download Full-text

Recurrent inhibition is increased in patients with spinal cord injury

Neurology ◽

10.1212/wnl.42.11.2162 ◽

1992 ◽

Vol 42 (11) ◽

pp. 2162-2162 ◽

Cited By ~ 57

Author(s):

J. M. Shefner ◽

S. A. Berman ◽

M. Sarkarati ◽

R. R. Young

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Recurrent Inhibition ◽

Cord Injury

Download Full-text

Recurrent Conditioning in the Cat Spinal Cord

The Journal of General Physiology ◽

10.1085/jgp.43.3.495 ◽

1960 ◽

Vol 43 (3) ◽

pp. 495-502 ◽

Cited By ~ 11

Author(s):

Victor J. Wilson ◽

William H. Talbot

Keyword(s):

Spinal Cord ◽

Recurrent Inhibition ◽

Phase Variable ◽

No Inhibition ◽

Antidromic Stimulation ◽

Consistent Manner ◽

Differential Action

The action of cumulative doses of meprobamate on antidromic conditioning has been studied in spinal cats. Recurrent facilitation is greatly reduced or completely abolished by total doses ranging from 210 to 400 mg./kg. The depth of recurrent inhibition is not affected in a consistent manner by meprobamate, but the duration of inhibition is markedly increased in all experiments. This differential action of meprobamate on facilitation and inhibition can be utilized to study conditioning effects consisting of combined inhibition and facilitation. If conditioning starts with an inhibitory phase, variable in duration, followed by facilitation, meprobamate depresses the facilitation and reveals an extended inhibitory curve. Facilitation, however, is not always accompanied by inhibition, since in some cases facilitation is depressed and no inhibition is uncovered. The results of these experiments are discussed in relation to the various types of conditioning that have been produced by antidromic stimulation.

Download Full-text

Effects of nucleus raphe magnus(NRM) stimulation on polysynaptic pathways and recurrent inhibition in cat spinal cord

Neuroscience Research Supplements ◽

10.1016/0921-8696(89)90713-5 ◽

1989 ◽

Vol 9 ◽

pp. 89

Author(s):

Naomi Wada ◽

Yuuko Kawashima

Keyword(s):

Spinal Cord ◽

Recurrent Inhibition ◽

Nucleus Raphe Magnus ◽

Raphe Magnus

Download Full-text

Kv3 channels contribute to the excitability of sub-populations of spinal cord neurons in lamina VII

10.1101/2021.11.29.470360 ◽

2021 ◽

Author(s):

Pierce Mullen ◽

Nadia Pilati ◽

Charles H Large ◽

Jim Deuchars ◽

Susan A Deuchars

Keyword(s):

Spinal Cord ◽

Firing Frequency ◽

Neuronal Firing ◽

Recurrent Inhibition ◽

Inhibitory Neurons ◽

Spinal Cord Neurons ◽

Lumbosacral Spinal Cord ◽

Whole Cell Patch Clamp ◽

Neuronal Types ◽

Fast Firing

Autonomic parasympathetic preganglionic neurons (PGN) drive contraction of the bladder during micturition but remain quiescent during bladder filling. This quiescence is postulated to be due to recurrent inhibition of PGN by fast-firing adjoining interneurons. Here, we defined four distinct neuronal types within lamina VII of the lumbosacral spinal cord, where PGN are situated, by combining whole cell patch clamp recordings with k-means clustering of a range of electrophysiological parameters. Additional morphological analysis separated these neuronal classes into parasympathetic preganglionic populations (PGN) and a fast firing interneuronal population. Kv3 channels are voltage-gated potassium channels (Kv) that allow fast and precise firing of neurons. We found that blockade of Kv3 channels by tetraethylammonium (TEA) reduced neuronal firing frequency and isolated high-voltage-activated Kv currents in the fast-firing population but had no effect in PGN populations. Furthermore, Kv3 blockade potentiated the local and descending inhibitory inputs to PGN indicating that Kv3-expressing inhibitory neurons are synaptically connected to PGN. Taken together, our data reveal that Kv3 channels are crucial for fast and regulated neuronal output of a defined population that may be involved in intrinsic spinal bladder circuits that underpin recurrent inhibition of PGN.

Download Full-text