Chapter 11 Electrophysiology of neuropeptides in the sensory spinal cord

Publisher This chapter discusses electrophysiology of neuropeptides in the sensory spinal cord. The dorsal horn has historically been viewed as an important site of integration of sensory information from the periphery. Included in dorsal horn circuitry is not only the primary afferent synapse on to the second order neuron, but also significant regulatory mechanisms, expressed at presynaptic and postsynaptic levels, from feedback and feedforward local inhibitory and, perhaps, even some excitatory neurons, from largely inhibitory propriospinal neurons arising from extrasegmental levels, and from descending fibers arising from neurons in supraspinal levels. This chapter focuses on some of the neuropeptides implicated in this regulation, but this should not be construed to reflect in any way a diminution of the importance which must be attributed to the other chemicals implicated. The multitude of neurotransmitters and neuromodulators, including the neuropeptides, amino acids and other chemicals distributed in the dorsal horn, subserve this integratory role. Noxious stimulation of the periphery induces the release of both excitatory and inhibitory neuropeptides along with other neurotransmitters in the spinal cord. The differential actions of these peptides on the dorsal horn neurons thus, may bring in a myriad of complex changes to regulate the overall excitability of the neurons and, thereby, regulate the flow of information from the spinal cord to the higher areas.