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See detailPeripheral and central alterations affecting spinal nociceptive processing and pain at adulthood in rats exposed to maternal separation
Juif, Piere-Eric; Salio, Chiara; Zell, Vivien et al

in European Journal of Neuroscience (2016)

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See detailPeripheral and central alterations affecting spinal nociceptive processing and pain at adulthood in rats exposed to neonatal maternal deprivation
Juif, Pierre-Eric; Salio, Chiara; Zell, Vivien UL et al

in European Journal of Neuroscience (2016)

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See detailCorticosterone analgesia is mediated by the spinal production of neuroactive metabolites that enhance GABAergic inhibitory transmission on dorsal horn rat neurons.
Zell, Vivien; Juif, Pierre-Eric; Hanesch, Ulrike UL et al

in The European journal of neuroscience (2015)

Corticosterone (CORT) is a glucocorticoid produced by adrenal glands under the control of the hypothalamic-pituitary-adrenal axis. Circulating CORT can enter the central nervous system and be reduced to ... [more ▼]

Corticosterone (CORT) is a glucocorticoid produced by adrenal glands under the control of the hypothalamic-pituitary-adrenal axis. Circulating CORT can enter the central nervous system and be reduced to neuroactive 3alpha5alpha-reduced steroids, which modulate GABAA receptors. In the dorsal spinal cord, GABAergic transmission modulates integration of nociceptive information. It has been shown that enhancing spinal inhibitory transmission alleviates hyperalgesia and allodynia. Therefore, the spinal neuronal network is a pivotal target to counteract pain symptoms. Thus, any increase in spinal 3alpha5alpha-reduced steroid production enhancing GABAergic inhibition should reduce nociceptive message integration and the pain response. Previously, it has been shown that high levels of plasma glucocorticoids give rise to analgesia. However, to our knowledge, nothing has been reported regarding direct non-genomic modulation of neuronal spinal activity by peripheral CORT. In the present study, we used combined in vivo and in vitro electrophysiology approaches, associated with measurement of nociceptive mechanical sensitivity and plasma CORT level measurement, to assess the impact of circulating CORT on rat nociception. We showed that CORT plasma level elevation produced analgesia via a reduction in C-fiber-mediated spinal responses. In the spine, CORT is reduced to the neuroactive metabolite allotetrahydrodeoxycorticosterone, which specifically enhances lamina II GABAergic synaptic transmission. The main consequence is a reduction in lamina II network excitability, reflecting a selective decrease in the processing of nociceptive inputs. The depressed neuronal activity at the spinal level then, in turn, leads to weaker nociceptive message transmission to supraspinal structures and hence to alleviation of pain. [less ▲]

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See detailPlasma glucocorticoids differentially modulate phasic and tonic GABA inhibition during early postnatal development in rat spinal lamina II.
Zell, Vivien; Hanesch, Ulrike UL; Poisbeau, Pierrick et al

in Neuroscience Letters (2014), 578

Nociceptive processing is tuned by GABAA receptor-mediated inhibition in the spinal cord dorsal horn that undergoes postnatal maturation in rodents. These GABAergic inhibitory postsynaptic currents (IPSCs ... [more ▼]

Nociceptive processing is tuned by GABAA receptor-mediated inhibition in the spinal cord dorsal horn that undergoes postnatal maturation in rodents. These GABAergic inhibitory postsynaptic currents (IPSCs) are modulated by 3alpha5alpha-reduced steroids during early postnatal development in spinal cord lamina II. Thus an enhanced phasic inhibition is present in neonates and decreases over time. GABA can also activate extrasynaptic receptors, giving rise to tonic inhibition. In this study, we characterized the contribution of plasma corticosterone (CORT) to postnatal maturation of spinal phasic and, for the first time, tonic GABAergic inhibitions. We used Fisher and Lewis rat strains displaying respectively high and low hypothalamic-pituitary-adrenal axis reactivity, compared to control Sprague-Dawley rats. Measured plasma CORT levels were significantly higher in Fisher rats, which also displayed significantly higher mechanical nociceptive thresholds, supporting the hypothesis of an antinociceptive action of CORT. Recorded GABAA IPSCs shortened during maturation in all strains while remaining larger in Fisher rats. Blocking the 5alpha-reduction of steroids in Fisher rats produced a further decrease of IPSC deactivation time constant. In contrast, GABAA tonic inhibition progressively increased during maturation, without any difference among strains. In conclusion, we show that both phasic and tonic GABAergic inhibitions undergo postnatal maturation in lamina II. Moreover spinal production of 3alpha5alpha-reduced steroids that presumably derive from plasma CORT is correlated to spinal GABAA phasic (but not tonic) inhibition and to mechanical nociceptive thresholds. [less ▲]

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See detailCirculating Glucocorticoids Shape Phasic and Tonic GABA Inhibition in Lamina II of Rat Spinal Cord.
Zell, Vivien UL; Anton, Fernand UL; Hanesch, Ulrike UL et al

in FENS Abstr., vol. 6, p153, 6.22, 2012 (2012)

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See detailMaternal separation delays the functional establishment of ascending and descending nociceptive circuits in the rat spinal cord.
Juif, Pierre-Eric UL; Petit-Demoulière, Nathalie; Lacaud, Adrien et al

in FENS Abstr., vol.6, p326, 57.11, 2012 (2012)

Detailed reference viewed: 166 (4 UL)