The pars intercerebralis affects digestive activities of the American cockroach, Periplaneta Americana, via crustacean cardioactive peptide and allatostatin-A.
The pars intercerebralis affects digestive activities of the American cockroach, Periplaneta Americana, via crustacean cardioactive peptide and allatostatin-A.
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DOI：
10.1016/j.jinsphys.2012.06.010
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发表时间：
2013
影响因子：
2.2
通讯作者：
T. Matsui;T. Sakai;H. Satake;M. Takeda
中科院分区：
文献类型：
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作者：
T. Matsui;T. Sakai;H. Satake;M. Takeda
我们先前的报告表明，在恒定黑暗(DD)条件下，经大脑间部(PI)消融的美洲大蠊(PIX)表现出中肠肥大，α淀粉酶和蛋白酶活性显著增加。浸浴甲壳动物心脏活性多肽和生长抑素可刺激培养中肠的α-淀粉酶和蛋白酶活性。然而，大脑，特别是大脑间部和中肠消化活动之间的功能关系和调节机制仍有待研究。在此，我们研究了上述手术(PIX-DD)后蟑螂中肠内抗CCAP和AST的免疫组织化学反应性(IHCr)。在肌层和上皮中均可观察到三种类型的IHCr细胞：(1)仅CCAP-ir，(2)仅AST-ir，(3)两种反应共存。与保持恒定状态的假手术对照组(CNT-DD)相比，在DD的PIX后，三种类型的蛋白表达均显著增加，表明PI抑制了中肠上皮细胞CCAP和AST的表达。我们还发现，在中肠同时给予CCAP和AST1.5倍的α淀粉酶活性和1.4倍的蛋白水解酶活性。PIX-DD组CCAP-ir在肌层表达较强，AST-ir表达受抑制。虽然这些多肽对自发收缩的作用相反，但当上皮释放时，这些多肽都激活了消化酶系统。总体而言，肌层口胃神经中上调的AST-6和下调的CCAP产生相同的最终结果，即通过酶的激活和导致吞吐时间延长的缓慢蠕动来刺激消化活动(肥大)。
Our previous report showed that the pars intercerebralis (PI)-ablated cockroach, Periplaneta americana (PIX), exhibited hypertrophy and a significant increase in α-amylase and protease activities in the midgut under constant darkness (DD). Bath-applied crustacean cardioactive peptide (CCAP) and allatostatin (AST) stimulated α-amylase and protease activities in the dissected midgut cultured in medium. However, the functional relationship and regulatory mechanism between the brain, particularly the pars intercerebralis and the midgut digestive activity remain to be investigated. Here, we investigated the immunohistochemical reactivities (IHCr) against CCAP and AST in the midgut of cockroach subjected to the above operation (PIX-DD). Three types of IHCr cells were observed in both the muscle layer and the epithelium: (1) CCAP-ir only, (2) AST-ir only and (3) both reactivities are colocalized. The number of all three types increased intensively after PIX under DD compared with that of sham operated control that was kept under constant condition (CNT-DD), indicating that the PI suppresses the expression of CCAP and AST in the midgut epithelium. We also showed that co-administration of CCAP and AST to the midgut caused increases of 1.5-fold and 1.4-fold for α-amylase and protease activities, respectively, compared with application of either peptide above. On the other hand, CCAP-ir in the muscle layer was more strongly expressed but AST-ir was suppressed in PIX-DD. While these peptides showed opposite effects on spontaneous contraction, when epithelially released, these peptides both activated the digestive enzyme system. Overall, up-regulated AST-6 and down-regulated CCAP in the stomatogastric nerve in the muscle layer produce the same end result, that is, stimulation of digestive activity (hypertrophy) via both enzyme activation and the retarded peristalsis that leads to increased throughput time.