scholarly journals Connectivity of pacemaker neurons in the neonatal rat superficial dorsal horn

2015 ◽  
Vol 523 (7) ◽  
pp. 1038-1053 ◽  
Author(s):  
Jie Li ◽  
Elizabeth Kritzer ◽  
Neil C. Ford ◽  
Shahriar Arbabi ◽  
Mark L. Baccei
Keyword(s):  
Dorsal Horn ◽  
Neonatal Rat ◽  
Superficial Dorsal Horn ◽  
Pacemaker Neurons

Developmental Changes in the Fidelity and Short-Term Plasticity of GABAergic Synapses in the Neonatal Rat Dorsal Horn

2008 ◽  
Vol 99 (6) ◽  
pp. 3144-3150 ◽  
Author(s):  
Rachel A. Ingram ◽  
Maria Fitzgerald ◽  
Mark L. Baccei
Keyword(s):  
Spinal Cord ◽  
Dorsal Horn ◽  
Receptive Fields ◽  
Neuronal Firing ◽  
Neonatal Rat ◽  
Superficial Dorsal Horn ◽  
Short Term ◽  
Dorsal Horn Neurons ◽  
Gabaergic Synapses

The lower thresholds and increased excitability of dorsal horn neurons in the neonatal rat suggest that inhibitory processing is less efficient in the immature spinal cord. This is unlikely to be explained by an absence of functional GABAergic inhibition because antagonism of γ-aminobutyric acid (GABA) type A receptors augments neuronal firing in vivo from the first days of life. However, it is possible that more subtle deficits in GABAergic signaling exist in the neonate, such as decreased reliability of transmission or greater depression during repetitive stimulation, both of which could influence the relative excitability of the immature spinal cord. To address this issue we examined monosynaptic GABAergic inputs onto superficial dorsal horn neurons using whole cell patch-clamp recordings made in spinal cord slices at a range of postnatal ages (P3, P10, and P21). The amplitudes of evoked inhibitory postsynaptic currents (IPSCs) were significantly lower and showed greater variability in younger animals, suggesting a lower fidelity of GABAergic signaling at early postnatal ages. Paired-pulse ratios were similar throughout the postnatal period, whereas trains of stimuli (1, 5, 10, and 20 Hz) revealed frequency-dependent short-term depression (STD) of IPSCs at all ages. Although the magnitude of STD did not differ between ages, the recovery from depression was significantly slower at immature GABAergic synapses. These properties may affect the integration of synaptic inputs within developing superficial dorsal horn neurons and thus contribute to their larger receptive fields and enhanced afterdischarge.

scholarly journals Subpopulation-specific patterns of intrinsic connectivity in mouse superficial dorsal horn as revealed by laser scanning photostimulation

2013 ◽  
Vol 591 (7) ◽  
pp. 1935-1949 ◽  
Author(s):  
Masafumi Kosugi ◽  
Go Kato ◽  
Stanislav Lukashov ◽  
Gautam Pendse ◽  
Zita Puskar ◽  
...  
Keyword(s):  
Dorsal Horn ◽  
Laser Scanning ◽  
Superficial Dorsal Horn ◽  
Intrinsic Connectivity ◽  
Laser Scanning Photostimulation

The effects of iontophoretic clonidine on neurones in the rat superficial dorsal horn

Pain ◽  
1993 ◽  
Vol 53 (2) ◽  
pp. 137-145 ◽  
Author(s):  
J. Millar ◽  
F. E. OʼBrien ◽  
G. V. Williams ◽  
J. Wood
Keyword(s):  
Dorsal Horn ◽  
Superficial Dorsal Horn

Activation of NMDA receptors drives action potentials in superficial dorsal horn from neonatal rats

Neuroreport ◽  
2000 ◽  
Vol 11 (8) ◽  
pp. 1721-1727 ◽  
Author(s):  
Rita Bardoni ◽  
Pier Cosimo Magherini ◽  
Amy B. MacDermott
Keyword(s):  
Nmda Receptors ◽  
Dorsal Horn ◽  
Action Potentials ◽  
Superficial Dorsal Horn ◽  
Neonatal Rats

Ultrastructural Analysis of Ectopic Synaptic Boutons Arising From Peripherally Regenerated Primary Afferent Fibers

1999 ◽  
Vol 81 (4) ◽  
pp. 1636-1644 ◽  
Author(s):  
H. Richard Koerber ◽  
Karoly Mirnics ◽  
Anahid M. Kavookjian ◽  
Alan R. Light
Keyword(s):  
Dorsal Horn ◽  
Sensory Neurons ◽  
Ultrastructural Analysis ◽  
Peripheral Stimulus ◽  
Primary Sensory Neurons ◽  
Superficial Dorsal Horn ◽  
Primary Afferent ◽  
Afferent Fibers ◽  
Primary Afferent Fibers ◽  
Synaptic Boutons

Ultrastructural analysis of ectopic synaptic boutons arising from peripherally regenerated primary afferent fibers. The central axons of peripherally regenerated Aβ primary sensory neurons were impaled in the dorsal columns of α-chloralose-anesthetized cats 9–12 mo after axotomy. The adequate peripheral stimulus was determined, and the afferent fibers intracellularly stimulated while simultaneously recording the resulting cord dorsum potentials (CDPs). Fibers that successfully had reinnervated the skin responded to light tactile stimulation, and evoked CDPs that suggested dorsally located boutons were stained intracellularly with horseradish peroxidase (HRP). Two HRP-stained regenerated Aβ afferent fibers were recovered that supported large numbers of axon collaterals and swellings in laminae I, IIo, and IIi. Sections containing the ectopic collateral fibers and terminals in the superficial dorsal horn were embedded in plastic. Analyses of serial ultrathin sections revealed that ectopic projections from both regenerated fibers supported numerous synaptic boutons filled with clear round vesicles, a few large dense core vesicles (LDCVs) and several mitochondria (>3). All profiles examined in serial sections (19) formed one to three asymmetric axo-dendritic contacts. Unmyelinated portions of ectopic fibers giving rise to en passant and terminal boutons often contained numerous clear round vesicles. Several boutons (47%) received asymmetric contacts from axon terminals containing pleomorphic vesicles. These results strongly suggest that regenerated Aβ fibers activated by light tactile stimuli support functional connections in the superficial dorsal horn that have distinct ultrastructural features. In addition, the appearance of LDCVs suggests that primary sensory neurons are capable of changing their neurochemical phenotype.

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