在捕食者的攻击中幸存下来的最引人注目的适应之一是分离附属物,这一过程被称为自动切开术。这发生在各种动物身上,包括蜥蜴(尾巴),螃蟹(腿),和海星(武器)。对进化进行了广泛的调查,生态学,和自切开术的生物力学影响,1,2,3,但对控制动物自断的神经机制知之甚少。然而,已经报道了在海星中存在作为自创促进因子的肽的证据。4在研究海星Asteriasrubens中sulfakinin/胆囊收缩素型神经肽(ArSK/CCK1)的体内作用时,在5,6中,我们观察到该肽在一些动物中触发了手臂自断。此外,当ArSK/CCK1的注射与臂的机械夹紧相结合时,受试动物中85%发生夹钳臂的自切,46%的人还自动切除一个或多个其他手臂。相比之下,在注射水的夹住动物(对照)中没有观察到自切开.为了检查这些发现的生理相关性,我们分析了ArSK/CCK1在自切平面中的表达,A.rubens.7,8根据其体内作用,表达ArSK/CCK1的神经纤维在止血带肌肉中显示,在自动切开术期间和之后调节手臂收缩的肌肉带。我们得出的结论是,ArSK/CCK1在海星中起着自创促进因子的作用,因此它是第一个被鉴定为动物自创调节剂的神经肽。
One of the most remarkable adaptations to survive attacks from predators is to detach an appendage-a process known as
autotomy. This occurs in a variety of animals, including lizards (tail), crabs (legs), and starfish (arms). There has been extensive investigation of the evolution, ecology, and biomechanical impact of
autotomy,1,2,3 but little is known about neural mechanisms controlling
autotomy in animals. However, evidence for the existence of a peptide that acts as an autotomy-promoting factor in starfish has been reported.4 While investigating in vivo effects of a sulfakinin/cholecystokinin-type neuropeptide (ArSK/CCK1) in the starfish Asterias rubens,5,6 we observed that this peptide triggered arm autotomy in some animals. Furthermore, when injection of ArSK/CCK1 was combined with mechanical clamping of an arm, autotomy of the clamped arm occurred in 85% of animals tested, with 46% also autotomizing one or more other arms. In contrast, no
autotomy was observed in clamped animals that were injected with water (control). To examine the physiological relevance of these findings, we analyzed expression of ArSK/CCK1 in the autotomy plane, a specialized region at the base of the arms in A. rubens.7,8 In accordance with its in vivo effects, nerve fibers expressing ArSK/CCK1 were revealed in the tourniquet muscle, a band of muscle that mediates constriction of the arm during and after autotomy. We conclude that ArSK/CCK1 acts as an autotomy-promoting factor in starfish and as such it is the first neuropeptide to be identified as a regulator of
autotomy in animals.