What happens at the nerve terminal in the spinal cord?
The peripheral sensory nerve has its cell body at the dorsal ganglion. Its dendrites, which function as a nerve terminal, project into the spinal cord at lamina I and II.
Neurotransmitters such as substance P, neurokinin-1 (NK-1), calcitonin gene-related peptide (CGRP), and glutamate are released at the terminal in the dorsal horn. All of these transmitters are excitatory.
They provoke the influx of sodium and calcium into the cell of the second-order neuron.
The second-order neuron is in lamina I (Lissauer’s tract) or lamina II (substantia gelatinosa).
- Binshtok AM: Mechanisms of nociceptive transduction and transmission: a machinery for pain sensation and tools for selective analgesia. Rev Neurobiol 97:143-147, 2011.
- Woolf CJ, Ma Q: Nociceptors—noxious stimulus detectors. Neuron 55(3):353-364, 2007.