Short-term plasticity in turtle dorsal horn neurons mediated by L-type Ca2+ channels

Russo, Raúl E.; Hounsgaard, Jørn

doi:10.1016/0306-4522(94)90222-4

Cited by 101 publications

(94 citation statements)

References 34 publications

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“…The soma locations of flexion cells were similar to those of sensory interneurons activated by limb skin stimulation (Schouenborg et al, 1995) and wide dynamic range neurons (Craig, 2003;You et al, 2003;Sandrini et al, 2005) in mammalian dorsal horn and overlapped with those of burst-generating neurons (Russo and Hounsgaard, 1996b), plateau-generating neurons (Russo and Hounsgaard, 1996a), and neurons showing windup (Russo and Hounsgaard, 1994) in turtle dorsal horn. Dorsolateral commissural interneurons in embryonic tadpoles also have dorsal soma locations and mediate a disynaptic reflex in which stroking the trunk skin evokes contralateral axial muscle contraction (Li et al, 2003).…”

Section: Morphological Comparisons To Dorsal Horn Cells In Other Studiesmentioning

confidence: 60%

Spinal Interneurons That Are Selectively Activated during Fictive Flexion Reflex

Berkowitz¹

2007

J. Neurosci.

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Behavioral choices in invertebrates are mediated by a combination of shared and specialized circuitry, including neurons that are inhibited during competing behaviors. Less is known, however, about the neural mechanisms of behavioral choice in vertebrates. The spinal cord can appropriately select among several types of limb movements, including limb withdrawal (flexion reflex), scratching, and locomotion, and thus is conducive to examination of vertebrate mechanisms of behavioral choice. Flexion reflex can interrupt and reset the rhythm of scratching and locomotion, suggesting that a combination of shared and specialized circuitry contributes to these behaviors, but little is known about the interneurons involved. Here, I used in vivo intracellular recording and dye injection to identify a group of spinal interneurons that are strongly activated during fictive flexion reflex but inhibited during fictive scratching and fictive swimming. These flexion-selective interneurons are typically rhythmically hyperpolarized during fictive scratching and fictive swimming. This hyperpolarization can be maximal during the ipsilateral hip flexor bursts of rhythmic limb motor patterns, although these cells are strongly activated during the ipsilateral hip flexor bursts of fictive flexion reflex. Thus, these interneurons are relatively specialized for fictive limb withdrawal, rather than contributing to the hip flexor phase of multiple types of limb movements. These flexion-selective cells are physiologically and morphologically distinguishable from a recently described group of spinal interneurons (transverse interneurons) that are strongly activated during both fictive flexion reflex and fictive scratching. Thus, spinal interneurons with distinct behavioral roles may to some extent be morphologically distinguishable.

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Section: Morphological Comparisons To Dorsal Horn Cells In Other Studiesmentioning

confidence: 60%

Spinal Interneurons That Are Selectively Activated during Fictive Flexion Reflex

Berkowitz¹

2007

J. Neurosci.

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“…The role of L-type Ca 2+ -mediated plateau potentials in structural and functional plasticity events is not fully understood. In spinal cord dorsal horn neurons, Ca 2+ influx through L-type channels is a critical component of short-term synaptic plasticity (Morisset and Nagy 2000;Russo and Hounsgaard 1994). In the superior colliculus of neonatal rats, it is associated with the induction of long-term depression of retinocollicular transmission (Lo and Mize 2000).…”

Section: Discussionmentioning

confidence: 99%

L-Type Calcium Channel-Mediated Plateau Potentials in Barrelette Cells During Structural Plasticity

Erzurumlu

2002

Journal of Neurophysiology

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Development and maintenance of whisker-specific patterns along the rodent trigeminal pathway depends on an intact sensory periphery during the sensitive/critical period in development. Barrelette cells of the brain stem trigeminal nuclei are the first set of neurons to develop whiskerspecific patterns. Those in the principal sensory nucleus (PrV) relay these patterns to the ventrobasal thalamus, and consequently, to the somatosensory cortex. Thus PrV barrelette cells are among the first group of central neurons susceptible to the effects of peripheral damage. Previously we showed that membrane properties of barrelette cells are distinct as early as postnatal day 1 (PND 1) and remain unchanged following peripheral denervation in newborn rat pups (Lo and Erzurumlu 2001). In the present study, we investigated the changes in synaptic transmission. In barrelette cells of normal PND 1 rats, weak stimulation of the trigeminal tract (TrV) that was subthreshold for inducing Na + spikes evoked an excitatory postsynaptic potentialinhibitory postsynaptic potential (EPSP-IPSP) sequence that was similar to the responses seen in older rats . Infraorbital nerve transection at birth did not alter excitatory and inhibitory synaptic connections of the barrelette cells. These observations suggested that local neuronal circuits are already established in PrV at birth and remain intact after deafferentation. Strong stimulation of the TrV induced a sustained depolarization (plateau potential) in denervated but not in normal barrelette neurons. The plateau potential was distinct from the EPSP-IPSP sequence by 1) a sustained (>80 ms) depolarization above −40 mV; 2) a slow decline slope (<0.1 mV/ms); 3) partially or totally inactivated Na + spikes on the plateau; and 4) a termination by a steep decay (> 1 mV/ms) to a hyperpolarizing membrane level. The plateau potential was mediated by L-type Ca 2+ channels and triggered by a N-methyl-D-aspartate (NMDA) receptormediated EPSP. γ-aminobutyric acid-A (GABA A ) receptor-mediated IPSP dynamically regulated the latency and duration of the plateau potential. These results indicate that after neonatal peripheral damage, central trigeminal inputs cause a large and longlasting Ca 2+ influx through Ltype Ca 2+ channels in barrelette neurons. Increased Ca 2+ entry may play a key role in injuryinduced structural remodeling, and/or transsynaptic cell death.

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“…The variety of effects that can be produced by repetitive stimulation of C fibre afferents in different populations of dorsal horn neurones (Schouenborg & Sj6lund, 1983;Schouenborg & Dickenson, 1985;Alarcon & Cervero, 1990) and the fact that the SS and VS reflexes in the present experiments were recorded from the same population of motoneurones indicate that the differences in wind-up between somatic and visceral systems are not due to inherent differences in visceral and somatic C fibre afferents, nor to the properties of the motoneurones, but are a property of the network of spinal interneurones. There is also evidence that wind-up may be due to the intrinsic membrane properties of spinal neurones, since it can be elicited by both repetitive afferent stimulation and by repetitive intracellular current pulses (Russo & Hounsgaard, 1994). Excitability changes of the baseline reflexes as a result of repetitive stimulation of somatic or visceral afferents The baseline SS reflexes recorded in our experiments showed, when tested after the conditioning train had been applied to the somatic nerve, an increase in responsiveness similar to that previously described in hindlimb flexion reflexes after prolonged noxious stimuli (Sherrington, 1947;Woolf, 1983), or repeated high intensity electrical stimuli (Wall & Woolf, 1984).…”

Section: Somato-somaticmentioning

confidence: 99%

Excitability changes of somatic and viscero‐somatic nociceptive reflexes in the decerebrate‐spinal rabbit: role of NMDA receptors.

Laird

Rubia

Cerveró

1995

The Journal of Physiology

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Short-term plasticity in turtle dorsal horn neurons mediated by L-type Ca2+ channels

Cited by 101 publications

References 34 publications

Spinal Interneurons That Are Selectively Activated during Fictive Flexion Reflex

Spinal Interneurons That Are Selectively Activated during Fictive Flexion Reflex

L-Type Calcium Channel-Mediated Plateau Potentials in Barrelette Cells During Structural Plasticity

Excitability changes of somatic and viscero‐somatic nociceptive reflexes in the decerebrate‐spinal rabbit: role of NMDA receptors.

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