Modulatory effect of substance P on GABA-activated currents from rat dorsal root ganglion

Jun Qiang Si, Zhi Qin Zhang, Chun Xia Li, Li Feng Wang, Yun Lei Yang, Zhi Wang Li

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

AIM: To explore the modulatory effect of substance P (SP) on GABA-activated current of dorsal root ganglion (DRG) neurons in rat. METHODS: The whole-cell patch-clamp technique was used to record SP- and GABA-activated currents in neurons freshly dissociated from rat DRG neurons. Drugs were applied by rapid solution exchange. RESULTS: Application of SP (28/41, 68.5 %) and GABA (36/41, 88.2 %) could induce concentration-dependent inward current in some cells. SP-(10 μmol/L) and GABA (100 μmol/L)-activated inward currents were (244±83) pA (n=9) and (1.8±0.5) nA (n=13), respectively. The majority of GABA-activated current had obvious three processes, the peak value (Ip), the steady state (Iss) and the desensitization (Id). The desensitization of GABA-activated current was a biphasic process, including fast and slow desensitization. However, pre-application of SP (0.001-1 μmol/L) could inhibit the GABA-activated inward current which was identified to be GABAA receptor-mediated current. The inhibitory effects were concentration-dependent. The inhibitory effect of SP on the peak value of GABA-activated current was more than the steady state of GABA-activated current. The inhibition of GABA-activated current by SP (0.1 μmol/L) was related to the time after application of SP, the inhibition of GABA-activated currents by SP reached the peak at about 4 min (49.8%±7.2%, n=7, P<0.01) and took about 12 min to get a full recovery. The inhibition of GABA-activated currents by SP was almost completely removed after blockade of PKC by H-7 with the re-patch clamp. CONCLUSION: Pre-application of SP exerts a more strong inhibitory effect on the peak value of GABA-activated current than the steady state of GABA-activated current.

Original languageEnglish (US)
Pages (from-to)623-629
Number of pages7
JournalActa Pharmacologica Sinica
Volume25
Issue number5
StatePublished - May 1 2004
Externally publishedYes

Keywords

  • GABA
  • Patch-clamp techniques
  • Protein kinase C
  • Spinal ganglia
  • Substance P

ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)

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    Si, J. Q., Zhang, Z. Q., Li, C. X., Wang, L. F., Yang, Y. L., & Li, Z. W. (2004). Modulatory effect of substance P on GABA-activated currents from rat dorsal root ganglion. Acta Pharmacologica Sinica, 25(5), 623-629.