Gibbs Sara, DeGolier Teresa F
Department of Biological Sciences, Bethel University, 3900 Bethel Drive, St. Paul, Minnesota 55112, USA.
Comp Biochem Physiol A Mol Integr Physiol. 2008 Dec;151(4):682-6. doi: 10.1016/j.cbpa.2008.08.022. Epub 2008 Aug 27.
The effects of neurotensin (NT) and cholecystokinin (CCK) were studied on isolated crop-gizzard preparations of Lumbricus terrestris suspended in a smooth muscle organ bath. Changes in the amplitude and frequency of contractions associated with spontaneous motility were observed in response to neurotransmitters known to have an excitatory effect (acetylcholine) and an inhibitory effect (serotonin); and to the hormones NT and CCK, which in vertebrate models have both been shown to inhibit gastric motility. The overall contractile amplitude and frequency of crop-gizzard contractions were decreased in response to increasing concentrations of NT and CCK. In general, both hormone-induced responses were similar when compared at equal molar concentrations. Cholecystokinin, however, did exhibit a greater reduction in contractile frequency than NT. It is speculated that possible desensitization of earthworm NT-receptors to higher hormone concentrations resulted in a depressed maximal response in the concentration-response curve. Despite that possibility, the overall hormonal inhibition was statistically significant. These results infer that NT- and CCK-induced inhibition of crop-gizzard motility may have a modulatory role in the transport of nutrients and overall efficiency of worm metabolism.
研究了神经降压素（NT）和胆囊收缩素（CCK）对悬浮于平滑肌器官浴槽中的蚯蚓离体嗉囊-砂囊制剂的影响。观察了与自发运动相关的收缩幅度和频率的变化，这些变化是对已知具有兴奋作用（乙酰胆碱）和抑制作用（5-羟色胺）的神经递质，以及对激素NT和CCK的反应，在脊椎动物模型中，这两种激素均已被证明可抑制胃动力。随着NT和CCK浓度的增加，嗉囊-砂囊收缩的总体收缩幅度和频率降低。一般来说，在等摩尔浓度下比较时，两种激素诱导的反应相似。然而，胆囊收缩素在收缩频率上的降低确实比神经降压素更大。据推测，蚯蚓NT受体对较高激素浓度可能的脱敏作用导致浓度-反应曲线中的最大反应降低。尽管有这种可能性，但总体激素抑制作用具有统计学意义。这些结果表明，NT和CCK诱导的嗉囊-砂囊运动抑制可能在营养物质运输和蚯蚓代谢的整体效率中具有调节作用。
