P物质对大鼠骶髓后连合核神经元甘氨酸激活的氯电流的调控

采用制霉菌素穿孔膜片箍技术,研究了Ｐ物质对急性分离的大鼠骶髓后的核神经元士的宁敏感性甘氨酸反应的调控作用。在箍制电压为－４０ｍＶ时,ＳＰ时１ｍｍｏｌ／Ｌ－１μｍｏｌ／Ｌ之间呈浓度依赖性地增强３０μｍｏｌ／Ｌ甘氨酸激活的氯电流。ＳＰ既不改变ＩＧｌｙ的翻转电位,也不是影响Ｇｌｙ与其受体的亲和力。Ｓｐａｎｔｉｄｅ和选择性Ｎ中受体拮抗剂,Ｌ－６６８,１６９,可阻断ＳＰ的增强作用,而选择性ＮＫ２受体拮抗剂,

Modulation of glycine-activated chloride currents by substance P in rat sacral dorsal commissural neurons

The modulatory effect of substance P (SP) on strychnine-sensitive glycine (Gly) response was examined in neurons acutely dissociated from the rat sacral dorsal commissural nucleus (SDCN) using nystatin perforated patch recording configuration under voltage-clamp conditions. Application of SP potentiated 30 mumol/L Gly-activated chloride current (IGly) in a concentration-dependent manner over the range of 1 nmol/L to 1 mumol/L at a holding potential of -40 mV. SP neither changed the reversal potential of Gly response nor affected the affinity of Gly to its receptor. The SP potentiation effect could be blocked by spantide as well as a selective NK1 receptor antagonist, L-668, 169, but not by NK2 receptor antagonist, L-659, 877. The facilitatory action of SP on IGly could also be abolished by pretreatment with chelerythrine or KN-62 in different neurons, a finding suggesting that protein kinase C (PKC) or Ca2+/calmodulin-dependent protein kinase II (CaMK II) possibly contributes to an intracellular pathway of SP in the augmentation of IGly. The results imply that SP may suppress nociception in the spinal cord by potentiating Gly response.