Spinothalamic lamina I neurons selectively sensitive to histamine: a central neural pathway for itch.
We found a class of lamina I spinothalamic tract (STT) neurons selectively excited by iontophoretic histamine. The responses of this class of neurons parallel the pure itching sensation this stimulus elicits in humans, and match the responses of peripheral C-fibers that have similar selectivity. These neurons have distinct central conduction velocities and thalamic projections, indicating that they constitute a unique subset of STT neurons. These findings can explain why a lesion of the lateral STT disrupts itch along with pain and temperature sensations. Our findings provide strong evidence that itch is subserved by specific neural elements both peripherally and centrally.
Andrew
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Atkinson Pain Research Laboratory, Division of Neurosurgery, Barrow Neurological Institute, 350 W. Thomas Road, Phoenix, Arizona 85013, USA. dandrew@chw.edu
Craig
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AD
D000818:Animals; D002415:Cats; D006632:Histamine; D007478:Iontophoresis; D008161:Lumbosacral Region; D009149:Mustard Plant; D009412:Nerve Fibers / Q000502:physiology; D009431:Neural Conduction / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology*; D009475:Neurons, Afferent / Q000145:classification / Q000166:cytology / Q000502:physiology*; D010147:Pain Measurement; D010936:Plant Extracts; D010938:Plant Oils; D011537:Pruritus / Q000139:chemically induced / Q000503:physiopathology; D013133:Spinothalamic Tracts / Q000166:cytology / Q000502:physiology*; D013268:Stimulation, Chemical; D013788:Thalamus / Q000502:physiology; D013697:Thermosensing / Q000502:physiology
D010936:Plant Extracts; D010938:Plant Oils; D006632:Histamine; C027793:mustard oil