摘要
The expression of the types of tachykinin receptors in the dorsal root ganglion (DRG) neurons by means of Xenopus oocyte expressing system was studied. Poly(A) +RNAs were extracted from cat cervical and lumbar DRG. Two days after injection of Poly(A) +RNAs, the oocytes were recorded with the two electrode voltage clamp technique. In the oocytes injected with DRG poly(A) +RNA,[Sar 9,Met(O 2) 11 ] substance P(Sar SP, 1 μmol/L), neurokinin A (NKA,1 μmol/L) or [β Ala 8] neurokinin A (4-10) (Ala NKA, 1 μmol/L) produced an inward current comprising a rapid spike and a long sustained oscillatory component for several minutes. Sar SP induced response was blocked by NK 1 antagonist L 668, 169 (1 μmol/L), but not by NK 2 antagonist L 659,877(1μmol/L). In contrast, Ala NKA and NKA responses were only blocked by L 659,877. The oocytes injected with DH Poly(A) +RNA also responded to Sar SP and NKA with similar inward currents, which were selectively blocked by L 668,169 and L 659,877, respectively. These tachykinins induced responses had a potent desensitization. The present data indicate expression of NK 1 and NK 2 receptors in DRG neurons, suggesting that there may be tachykinin autoreceptors on the nociceptive primary afferent terminals.
The expression of the types of tachykinin receptors in the dorsal root ganglion (DRG) neurons by means of Xenopus oocyte expressing system was studied. Poly(A) +RNAs were extracted from cat cervical and lumbar DRG. Two days after injection of Poly(A) +RNAs, the oocytes were recorded with the two electrode voltage clamp technique. In the oocytes injected with DRG poly(A) +RNA,[Sar 9,Met(O 2) 11 ] substance P(Sar SP, 1 μmol/L), neurokinin A (NKA,1 μmol/L) or [β Ala 8] neurokinin A (4-10) (Ala NKA, 1 μmol/L) produced an inward current comprising a rapid spike and a long sustained oscillatory component for several minutes. Sar SP induced response was blocked by NK 1 antagonist L 668, 169 (1 μmol/L), but not by NK 2 antagonist L 659,877(1μmol/L). In contrast, Ala NKA and NKA responses were only blocked by L 659,877. The oocytes injected with DH Poly(A) +RNA also responded to Sar SP and NKA with similar inward currents, which were selectively blocked by L 668,169 and L 659,877, respectively. These tachykinins induced responses had a potent desensitization. The present data indicate expression of NK 1 and NK 2 receptors in DRG neurons, suggesting that there may be tachykinin autoreceptors on the nociceptive primary afferent terminals.
基金
ProjectsupportedbytheNationalNaturalScienceFoundationofChina (GrantNo .39370 2 4 9)
