作　　者： ; ; ; ; ; ; ;

机构地区： 安徽医科大学

出　　处： 《生理学报》 2003年第4期388-394,共7页

摘　　要： 应用细胞内记录技术,对铃蟾肽(bombesin,BOM)在豚鼠离体肠系膜下神经节(inferior mesenteric ganglion,IMG)非胆碱能兴奋性突触传递中的作用进行了研究。重复电刺激突触前结肠神经,有74.3％(52/70)IMG细胞可诱发迟慢兴奋性突触后电位(ls-EPSP)。在可引出ls-EPSP的细胞中,22％(4/18)细胞同时对BOM和SP敏感。用BOM持续灌流IMG,可明显抑制对BOM敏感细胞的ls-EPSP,对BOM不敏感细胞的ls-EPSP则无影响,且BOM受体与SP受体间无交叉脱敏。BOM受体阻断剂tyT^4[D-phe^(12)]bombesin能明显可逆性地抑制BOM敏感细胞的ls-EPSP和去极化,但对BOM不敏感细胞则无影响。研究结果提示,BOM可能是介导豚鼠IMG细胞ls-EPSP的一种递质。 The effect of bombesin (BOM) on non-cholinergic excitatory synaptic transmission of the guinea pig inferior mesenteric ganglion (IMG) was investigated by intracellular recording. Repetitive stimulation of the colon nerves (1ms, 25Hz, 4s) elicited a burst of action potentials, which was followed by a long-lasting depolarization in 74.3% (52/70) of the IMG neurons. The depolarization was not blocked by nicotinic (d-tubocurarine, 100 μmol/L) and muscarinic (atropine, 1 μmol/L) antagonists, but was eliminated in a low Ca^(2+)/high Mg^(2+) Krebs solution, indicating that the depolarization was due to the release of non-cholinergic transmitters. Superfusing the ganglia with BOM (10μmoL/L, 1min) induced a slow depolarization in 66.5% (109/164) neurons tested. The BOM response was not appreciably changed in low Ca^(2+)/high Mg^(2+) Krebs solution (n=6, P>0. 05), suggesting that BOM depolarized the neurons by acting directly on the postsynaptic membrane rather than via a release of other endogenous depolarizing substances. In a total of 102 cells that exhibited late slow excitatory postsynaptic potential (ls-EPSP), suporfusion of the ganglia with BOM produced a membrane depolarization in 82 neurons (80%), while the remaining 20 cells (20%) exhibited no response to BOM. In 18 neurons with ls-EPSP, 4 (22%) neurons were sensitive to both BOM and SP; 6 (33%) and 5 (28%) neurons were only sensitive to BOM and SP, respectively. The remaining 3 (17%) neurons were insensitive to both BOM and SP. Membrane resistance (R_m) had no apparent change in 47.3%, 59.5% of the neurons tested during the ls-EPSP (n=55 ) and BOM depolarization(n=84), respectively, but had a marked decrease in 38.2%, 27.4%, and a marked increase in the remaining 14.5%, 13.1% of the neurons. However, when the R_m change accompanying ls-EPSP was com- pared with that accompanying BOM depolarization (n=20) in the same neuron, the changes in R_m were always parallel. Moreover, ls-EPSP (n=6) and BOM depolarization (n=8) were all augmented by conditioning hyperpola

关 键 词： 铃蟾肽 物质 迟慢兴奋性突触后电位 肠系膜下神经节 豚鼠

领　　域： [生物学] [生物学]