PNAS 1979-01-01

Enkephalin inhibits release of substance P from sensory neurons in culture and decreases action potential duration.

A W Mudge, S E Leeman, G D Fischbach

Index: Proc. Natl. Acad. Sci. U. S. A. 76(1) , 526-530, (1979)

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Abstract

Sensory neurons grown in dispersed cell culture in the absence of non-neuronal cell types contain immunoreactive substance P that is chemically similar to synthetic substance P. When depolarized in high-K+ media (30-120 mM), the neurons release this peptide by a Ca2+-dependent mechanism. An enkephalin analogue, [D-Ala2]enkephalin amide, at 10 micron inhibits the K+-evoked release of substance P. At the same or lower concentrations, [D-Ala2]enkephalin amide and enkephalin decrease the duration of the Ca2+ action potential evoked and recorded in dorsal root ganglion cell bodies without affecting the resting membrane potential or resting membrane conductance. This modulation of voltage-sensitive channels may account for the inhibition of substance P release.