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This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 580/3/815    most recent jphysiol.2007.128314v1 Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kato, G. Articles by Strassman, A. M. Search for Related Content PubMed PubMed Citation Articles by Kato, G. Articles by Strassman, A. M. Related Collections Neuroscience

Departments of
¹ Anaesthesia and Critical Care, Beth Israel Deaconess Medical Center
² Anaesthesia and Pain Research Centre, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA

The substantia gelatinosa (lamina II) of the spinal dorsal horn contains inhibitory and excitatory interneurons that are thought to play a critical role in the modulation of nociception. However, the organization of the intrinsic circuitry within lamina II remains poorly understood. We used glutamate uncaging by laser scanning photostimulation to map the location of neurons that give rise to local synaptic inputs to islet cells, a major class of inhibitory interneuron in lamina II. We also mapped the distribution of sites on the islet cells that exhibited direct (non-synaptic) responses to uncaging of excitatory and inhibitory transmitters. Local synaptic inputs to islet cells arose almost entirely from within lamina II, and these local inputs included both excitatory and inhibitory components. Furthermore, there was a striking segregation in the location of sites that evoked excitatory versus inhibitory synaptic inputs, such that inhibitory presynaptic neurons were distributed more proximal to the islet cell soma. This was paralleled in part by a differential distribution of transmitter receptor sites on the islet cell, in that inhibitory sites were confined to the peri-somatic region while excitatory sites were more widespread. This differential organization of excitatory and inhibitory inputs suggests a principle for the wiring of local circuitry within the substantia gelatinosa.

(Received 15 January 2007; accepted after revision 5 February 2007; first published online 8 February 2007)
Corresponding author G. Kato: Department of Anaesthesia and Critical Care, DA-719, Beth Israel Deaconess Medical Center, 330 Brookline Ave., Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02215, USA. Email: gkato{at}bidmc.harvard.edu