Substance P, a putative peptide neurotransmitter contained in primary sensory neurons, is suggested to play a major role in nociceptive transmission. In the present study, the existence of substance P autoreceptor in dorsal root ganglion neurons was identified with a method we developed recently and substance P-activated inward current in the dorsal root ganglion neurons and its ionic mechanism were also explored preliminarily. The majority of the cells examined (68/76, 89.5%) were sensitive to external application of substance P (0.01-10 μM) with a concentration-dependent inward current. This current was found to result from the opening of nonselective ion channel, preferring the Na+ channel. The substance P-activated current can be suppressed by Cd2+ (0.05 μM), which suggested Ca2+ may also be involved. Soon after the neurons had been identified to be endowed with substance P receptor with whole-cell patch-clamp technique, 17 cells were chosen for immunocytochemical staining to detect substance P-immunoreactivity. Seven neurons which were classified into small and intermediate size were found to reveal substance P-immunoreactivity. Using this method we have identified the existence of substance P autoreceptor in rat DRG neurons.

Original languageEnglish
Pages (from-to)535-541
Number of pages7
Issue number2
StatePublished - 1997


  • autoreceptor
  • dorsal root ganglion
  • immunocytochemistry
  • substance P
  • whole-cell recording


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