![]() The study began a few years back when Love catalogued the genes whose activity changes in a regenerating tail. These rowdy chemicals are essential for the animal’s healing prowess. Love found that antioxidants actually hamper a tadpole’s ability to regenerate a severed tail, precisely because they mop up ROS. The view that ROS are “bad” is so widespread that antioxidants have almost become synonymous with good health. As such, people often cast ROS as harmful villains that need to be “mopped up”, and antioxidants are the heroes for the job. They’re like chemical bulls in china shops, energetically destroying whatever’s around them. But when their numbers increase, ROS can wreak havoc on our cells by reacting with, and damaging, important molecules like protein and DNA. We produce them through the act of living, and we depend on them to coordinate the various chemical events within our cells. They’re called “ reactive oxygen species” (ROS), or more colloquially as “free radicals”-small molecules that contain oxygen atoms and are highly reactive. Now, Nick Love from the University of Manchester has found that the tadpole’s healing powers depend on a group of chemicals that are often caricaturised as unwanted villains. Humans can only dream of such amazing regeneration and many scientists are trying to understand how it works. ![]() ![]() Sequential activation of CN V, VII, X were observed during gill ventilation of in vivo and fictive gill ventilation in vitro, whereas these nerve activities, along with SN II displayed more synchronous bursting patterns of activation during lung ventilation and fictive lung breaths.If a tadpole loses its tail, it can simply grow another. Both in vivo and in vitro studies revealed two distinct neural bursting patterns associated with gill and lung ventilation. These data demonstrate that the neural substrate required for fictive gill and lung ventilation exists in anatomically separate regions such that the gill central pattern generator (CPG) is located in the caudal medulla at the level of CN X throughout development, whereas the location of the lung CPG is located more rostrally at the level of CN VII in the post-metamorphic larva. Preliminary data reveal that robust gill ventilation was recorded consistently only if the segment of brainstem included CN X, whereas the loci capable of eliciting fictive lung bursting patterns appeared to differ depending on developmental stage. A second transection was then made between the caudal margin of CN X and rostral to SN II. The brainstem was transected between CN VIII and IX and the response to changes in PCO2 was recorded. To investigate the neural substrates responsible for central respiratory rhythm generation of gill and lung ventilation in the developing tadpole, we recorded efferent activities of cranial nerve (CN) V, VII, and X and spinal nerve (SN) II during changes in superfusate PCO2 before and after multiple transection of the in vitro brainstem. Fictive gill and lung ventilation in the pre- and post-metamorphic tadpole brainstem, J Neurophysiol 1998, in press). In addition, the ontogenetic dependence of central respiratory chemoreceptor stimulation on fictive gill and lung ventilation has been previously described (Torgerson CS, Gdovin MJ, Remmers JE. Lexington: University of Kentucky Press, 1993:52-57). Respiratory Control Central and Peripheral Mechanisms. Comparative approach to neural control of respiration, In: Speck DF, Dekin MS, Revelette WR, Frazier DT, editors. ![]() Neurorespiratory pattern of gill and lung ventilation in the decerebrate spontaneously breathing tadpole, Respir Physiol 1998 113:135 146 Pack AI, Galante RJ, Walker RE, Kubin LK, Fishman AP. ![]() Characterization of gill and lung ventilatory activity in cranial nerves in the spontaneously breathing tadpole Rana catesbeiana, FASEB J 1996 10(3):A642 Gdovin MJ, Torgerson CS, Remmers JE. Spontaneous high-frequency, low-amplitude and low-frequency, high-amplitude efferent bursting patterns of cranial and spinal motor nerve activity in the in vitro brainstem preparation of the bullfrog tadpole Rana catesbeiana have been characterized as fictive gill and lung ventilation, respectively (Gdovin MJ, Torgerson CS, Remmers JE). ![]()
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