RT Journal Article SR Electronic T1 A Specific Inhibitory Pathway between Substantia Gelatinosa Neurons Receiving Direct C-Fiber Input JF The Journal of Neuroscience JO J. Neurosci. FD Society for Neuroscience SP 8752 OP 8758 DO 10.1523/JNEUROSCI.23-25-08752.2003 VO 23 IS 25 A1 Lu, Yan A1 Perl, Edward R. YR 2003 UL http://www.jneurosci.org/content/23/25/8752.abstract AB The spinal substantia gelatinosa (SG) is a major termination region for unmyelinated (C) primary afferent fibers; however, how the input it receives from these sensory fibers is processed by SG neurons remains primarily a matter of conjecture. To gain insight on connections and functional interactions between intrinsic SG neurons, simultaneous tight-seal, whole-cell recordings were made from pairs of neurons in rat spinal cord slices to examine whether impulses in one cell generated synaptic activity in the other. Most SG neuron pairs sampled lacked synaptic interaction. Those showing a linkage included a recurring pattern consisting of a monosynaptic, bicuculline-sensitive inhibitory connection from an islet cell to a transient central neuron, each of which received direct excitatory input from different afferent C-fibers. This newly defined inhibitory circuit is postulated to represent a SG neural module by which a nociceptive C-fiber input to transient central cells is modified by other C-fiber messages.