The endotoxin lipopolysaccharides (LPS), secreted from gram-negative bacteria, has direct effects on synaptic transmission independent of systemic secondary cytokine responses. High concentration of LPS (500 μg/mL) from Serratia marcescens increased synaptic efficacy at glutamatergic low-output synapses more than for high-output synapses. Over an hour of exposure was not toxic to the preparation and continued to enhance synaptic transmission. A small but significant rapid hyperpolarization of the post-synaptic cells occurred, in addition to a slower enhancement of in the amplitude of evoked excitatory junction potentials. LPS may promote reserve pool vesicles to the readily releasable pool for low-output synapses. The action of LPS at the glutamatergic synapses of the crayfish neuromuscular junction is unique in promoting synaptic transmission as compared to other glutamatergic synapses in Drosophila and mammals, where synaptic transmission is depressed.

革兰氏阴性菌分泌的内毒素脂多糖 (LPS) 对突触传递具有直接影响，而与全身次级细胞因子反应无关。来自粘质沙雷氏菌的高浓度 LPS (500 μg/mL)与高输出突触相比，谷氨酸能低输出突触的突触功效增加。一个多小时的接触对制剂没有毒性，并继续增强突触传递。除了诱发兴奋性连接电位的幅度较慢的增强外，还发生了突触后细胞的小但显着的快速超极化。LPS 可以将储备池囊泡促进为低输出突触的易于释放的池。与抑制突触传递的果蝇和哺乳动物中的其他谷氨酸能突触相比，LPS 在小龙虾神经肌肉接头的谷氨酸能突触中的作用在促进突触传递方面是独一无二的。