Substance P in principal sympathetic neurons: regulation by impulse activity

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Science  16 Oct 1981:
Vol. 214, Issue 4518, pp. 335-336
DOI: 10.1126/science.6169153


Regulation of the putative peptide neurotransmitter substance P was examined in the superior cervical sympathetic ganglion of the neonatal rat. Surgical decentralization (denervation) of the superior cervical ganglion increased ganglion substance P content. In cultured ganglia, the amount of substance P increased more than 50-fold after 48 hours, and this rise was dependent on protein and RNA synthesis. Veratridine prevented the increase in substance P in vitro, and tetrodotoxin blocked the veratridine effect; this suggests that sodium influx and membrane depolarization prevent substance P elevation. Immunohistochemical analysis of cultured ganglia indicated that substance P was present in the perikarya of principal sympathetic neurons and in ganglionic nerve processes. Transsynaptic impulses, through the mediation of postsynaptic sodium influx, may decrease substance P in sympathetic neurons.