Abstract
Chronic itch is symptomatic of many skin conditions and systemic diseases. Little is known about pathophysiological alterations in itch-signaling neural pathways associated with chronic itch. We used a mouse model of hindpaw chronic dry skin itch to investigate properties of presumptive itch-signaling neurons. Neurons in the lumbar superficial dorsal horn ipsilateral to hindpaw dry skin treatment exhibited a high level of spontaneous activity that was inhibited by scratching the plantar surface. Most spontaneously active units exhibited further increases in firing rate following intradermal injection of an agonist of the protease-activated receptor PAR-2, or histamine. The large majority of pruritogenresponsive units also responded to capsaicin and allyl isothiocyanate. For neurons ipsilateral to dry skin treatment, responses elicited by the PAR-2 agonist, but not histamine or mechanical stimuli, were significantly larger compared with neurons ipsilateral to vehicle (water) treatment or neurons recorded in naïve (untreated) mice. The spontaneous activity may signal ongoing itch, while enhanced PAR-2 agonist-evoked responses may underlie hyperknesis (enhanced itch), both of which are symptomatic of many chronic itch conditions. The enhancement of neuronal responses evoked by the PAR-2 agonist, but not by histamine or mechanical stimuli, implies that the dry skin condition selectively sensitized PAR-2 agonist-sensitive primary afferent pruriceptors.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2811-2817 |
| Number of pages | 7 |
| Journal | Journal of Neurophysiology |
| Volume | 105 |
| Issue number | 6 |
| DOIs | |
| State | Published - Jun 1 2011 |
| Externally published | Yes |
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Keywords
- Intradermal
- Protease-activated receptor
ASJC Scopus subject areas
- Neuroscience(all)
- Physiology
Cite this
Enhanced responses of lumbar superficial dorsal horn neurons to intradermal PAR-2 agonist but not histamine in a mouse hindpaw dry skin itch model. / Akiyama, Tasuku; Carstens, Mirela Iodi; Carstens, E.
In: Journal of Neurophysiology, Vol. 105, No. 6, 01.06.2011, p. 2811-2817.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Enhanced responses of lumbar superficial dorsal horn neurons to intradermal PAR-2 agonist but not histamine in a mouse hindpaw dry skin itch model
AU - Akiyama, Tasuku
AU - Carstens, Mirela Iodi
AU - Carstens, E.
PY - 2011/6/1
Y1 - 2011/6/1
N2 - Chronic itch is symptomatic of many skin conditions and systemic diseases. Little is known about pathophysiological alterations in itch-signaling neural pathways associated with chronic itch. We used a mouse model of hindpaw chronic dry skin itch to investigate properties of presumptive itch-signaling neurons. Neurons in the lumbar superficial dorsal horn ipsilateral to hindpaw dry skin treatment exhibited a high level of spontaneous activity that was inhibited by scratching the plantar surface. Most spontaneously active units exhibited further increases in firing rate following intradermal injection of an agonist of the protease-activated receptor PAR-2, or histamine. The large majority of pruritogenresponsive units also responded to capsaicin and allyl isothiocyanate. For neurons ipsilateral to dry skin treatment, responses elicited by the PAR-2 agonist, but not histamine or mechanical stimuli, were significantly larger compared with neurons ipsilateral to vehicle (water) treatment or neurons recorded in naïve (untreated) mice. The spontaneous activity may signal ongoing itch, while enhanced PAR-2 agonist-evoked responses may underlie hyperknesis (enhanced itch), both of which are symptomatic of many chronic itch conditions. The enhancement of neuronal responses evoked by the PAR-2 agonist, but not by histamine or mechanical stimuli, implies that the dry skin condition selectively sensitized PAR-2 agonist-sensitive primary afferent pruriceptors.
AB - Chronic itch is symptomatic of many skin conditions and systemic diseases. Little is known about pathophysiological alterations in itch-signaling neural pathways associated with chronic itch. We used a mouse model of hindpaw chronic dry skin itch to investigate properties of presumptive itch-signaling neurons. Neurons in the lumbar superficial dorsal horn ipsilateral to hindpaw dry skin treatment exhibited a high level of spontaneous activity that was inhibited by scratching the plantar surface. Most spontaneously active units exhibited further increases in firing rate following intradermal injection of an agonist of the protease-activated receptor PAR-2, or histamine. The large majority of pruritogenresponsive units also responded to capsaicin and allyl isothiocyanate. For neurons ipsilateral to dry skin treatment, responses elicited by the PAR-2 agonist, but not histamine or mechanical stimuli, were significantly larger compared with neurons ipsilateral to vehicle (water) treatment or neurons recorded in naïve (untreated) mice. The spontaneous activity may signal ongoing itch, while enhanced PAR-2 agonist-evoked responses may underlie hyperknesis (enhanced itch), both of which are symptomatic of many chronic itch conditions. The enhancement of neuronal responses evoked by the PAR-2 agonist, but not by histamine or mechanical stimuli, implies that the dry skin condition selectively sensitized PAR-2 agonist-sensitive primary afferent pruriceptors.
KW - Intradermal
KW - Protease-activated receptor
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U2 - 10.1152/jn.01124.2010
DO - 10.1152/jn.01124.2010
M3 - Article
VL - 105
SP - 2811
EP - 2817
JO - Journal of Neurophysiology
JF - Journal of Neurophysiology
SN - 0022-3077
IS - 6
ER -