Search for Transglutaminase Activity Change accompanying with Synaptic Transmission Process

颈上交感神经节(SCG)含有许多胆碱能突触，并在大鼠切除后维持冲动传递活动。当在生理盐水中加入神经递质(乙酰胆碱；Ach)时，分离的SCG在有氧孵育过程中，Ca~(2+)依赖性酶-转谷氨酰胺酶(TG)的活性迅速而显著地升高。乙酰胆碱酯酶激动剂卡巴胆碱在几分钟内可显著增加组织中甘油三酯的活性，该作用可被乙酰胆碱酯酶拮抗剂阿托品拮抗。一氧化氮(NO)是一种新的递质候选物质，它能显著促进SCG中TG的活性，并被NO合酶的特异性抑制剂N^G-单甲基-L-精氨酸抑制。NO的活化率是通过形成环状GMP来衡量的，但鸟苷酸环化酶抑制剂亚甲蓝不能抑制Carb诱导的TG活性的增加。这些结果提示，Carb对SCG神经元的刺激通过受体介导的NO和环化GMP增加启动了TG激活的细胞内信号传递过程，从而导致细胞内Ca~(2+)和Gt~(2+)升高。

Superior cervical sympathtic ganglion (SCG) contains many cholinergic synapses, and maintains impulse transmission activity after removal from the rat. When neurotransmitter (acetylcholine ; Ach) was applied to the physiological saline medium during aerobic incubation of the excised SCG,rapid and significant rise in activity of Ca^<2+> -dependent eNzyme, transglutaminase (TG) was observed. Carbachol, a muscarinic ACh agonist, strongly increased the tissue TG activity within minutes, which was fairly antagonized by a muscarinic ACh antagonist, atropine. Nitric oxide (NO), a new transmitter candidate, remarkably accelerated TG activity in the SCG,and the activity was suppressed by a specific inhibitor for NO synthase, N^G -monomethyl-L-arginine. The rate of NO activation was measured byh the formation of cyclic GMP,but the an inhibitor of guanylate cyclase, methylene blue, did not supressed the Carb-induced TG activity increase. These results suggest that Carb -stimulation to the SCG neurons initiate the intracellular signal transfer process for the activation of TG via receptor mediated NO and cyclic GMP increase to cause intracellular Ca^<2+> rise.