Escaping through the predator's gill cleft: A defensive tactic of juvenile eels after capture by predatory fish

Some prey animals can actively escape from predators even after being captured, but knowledge of such behaviors is still limited, especially in vertebrates. Here, we report the unique active escape behavior of Japanese eel Anguilla japonica juveniles through the gill cleft of the predatory fish Odontobutis obscura. Of the 54 A. japonica juveniles captured by the predator, 28 escaped via the predator's gill, and most escaped individuals survived afterwards. In all escaped individuals, their tails emerged first from the gill cleft of the predator, and then their whole bodies slipped out in a backward direction from the cleft. These findings indicate that A. japonica juveniles have the specialized antipredator tactic, which provides the basis for further investigation from behavioral, ecological, and evolutionary perspectives.

A limbic circuit selectively links active escape to food suppression

Stress has pleiotropic physiologic effects, but the neural circuits linking stress to these responses are not well understood. Here, we describe a novel population of lateral septum neurons expressing neurotensin (LSNts) in mice that are selectively tuned to specific types of stress. LSNts neurons increase their activity during active escape, responding to stress when flight is a viable option, but not when associated with freezing or immobility. Chemogenetic activation of LSNts neurons decreases food intake and body weight, without altering locomotion and anxiety. LSNts neurons co-express several molecules including Glp1r (glucagon-like peptide one receptor) and manipulations of Glp1r signaling in the LS recapitulates the behavioral effects of LSNts activation. Activation of LSNts terminals in the lateral hypothalamus (LH) also decreases food intake. These results show that LSNts neurons are selectively tuned to active escape stress and can reduce food consumption via effects on hypothalamic pathways.

DL-3-n-butylphthalide improved physical and learning and memory performance of rodents exposed to acute and chronic hypobaric hypoxia

Background: Studies revealed the protective effect of DL-3-n-butylphthalide (NBP) against ischemic hypoxia diseases. However, the role of NBP in animals with hypobaric hypoxia is elusive. This study investigated the effect of NBP on animals with acute and chronic hypobaric hypoxia. Methods: SD rats and Kunming mice administrated with NBP ( 90, 180 and 360 mg/kg for mice, 60, 120, and 240 mg/kg for rats and 90, 180 and 360 mg/kg for mice 60, 120, and 240 mg/kg for rats ) were placed located in 10,000 m hypobaric hypoxia chamber. And survival analysis of animals implied that NBP could significantly improve and survival percent at 30 min were analyzed . Then, drug treated animals rats (mice) were evaluated for exhaustive exhausted time and exhaustive exhausted distance in forced exercise wheel-track treadmill and treadmill running and motor-driven wheel-track treadmill experiments at 5,800 m (5,000 m) for 3 or 21 days or 21 days , to evaluate changes of physical functions. Rats were also evaluated for times of active escape , and average time of active escape , time of passive escape, and average time of passive escape in a shuttle-box experiment at 5,800 m for 7 days or 28 days 7 or 28 days , to evaluate changes of cognitive learning and memory function s . ATP level was evaluated measured in the gastrocnemius muscle and maloaldehyde (MDA), superoxide dismutase (SOD), hydrogen peroxide (H 2 O 2 ), lactate, and glutathione peroxiase (GSH-Px) measurements and routine blood tests were detected in serum of rats . Results: Survival analysis in 10,000 m indicated NBP could improve hypoxia tolerance ability. Exhaustive Exhausted time for rats (NBP, 120 and 240 mg/kg) and exhaustive exhausted time and distance for mice (NBP, 90 mg/kg) significantly increased under acute hypoxia. And NBP treatment also significantly increased the exhaustive exhausted time for rats under chronic hypoxia. Moreover, NBP of 120 and 240 mg/kg significantly increased the average time s of passive active escape under acute and chronic hypoxia. These results suggested that NBP could improve physical and cognitive learning and memory functions under acute and chronic hypobaric hypoxia. Furthermore, the levels of MDA and H 2 O 2 decreased but those of SOD and GSH-Px in serum of rats increased under acute and chronic hypoxia. Furthermore, Additionally, the content of ATP in gastrocnemius muscle significantly increased, while lactate in serum level significantly decreased. The results presented suggested that NBP could regulate redox homeostasis and improve energy metabolism of hypobaric hypoxic rats. Conclusion: NBP could improve physical and cognitive learning and memory functions under acute and chronic hypobaric hypoxia by increasing anti-oxidative capacity and energy supply.

DL-3-n-Butylphthalide Improves Physical and Cognitive Performance of Animals with Acute and Chronic Hypobaric Hypoxia

Background: Studies revealed the protective effect of DL-3-n-butylphthalide (NBP) against ischemic hypoxia diseases. However, the role of NBP in animals with hypobaric hypoxia is elusive. This study investigated the effect of NBP on animals with acute and chronic hypobaric hypoxia.Methods: SD rats and Kunming mice administrated with NBP (90, 180 and 360 mg/kg for mice, and 60, 120, and 240 mg/kg for rats) were located in 10,000 m hypobaric hypoxia chamber. And survival analysis of animals implied that NBP could significantly improve survival percent at 30 min. Then, treated animals were evaluated for exhaustive time and exhaustive distance in forced exercise wheel-track treadmill and treadmill running experiments at 5,800 m for 3 or 21 days, to evaluate physical functions. Rats were also evaluated for times of active escape, average time of active escape, time of passive escape, and average time of passive escape in a shuttle-box experiment at 5,800 m for 7 or 28 days, to evaluate cognitive functions. ATP level was evaluated in the gastrocnemius muscle and maloaldehyde (MDA), superoxide dismutase (SOD), hydrogen peroxide (H2O2), lactate, and glutathione peroxiase (GSH-Px) measurements and routine blood tests were detected.Results: Exhaustive time for rats (NBP, 120 and 240 mg/kg) and exhaustive time and distance for mice (NBP, 90 mg/kg) significantly increased under acute hypoxia. And NBP treatment significantly increased the exhaustive time for rats under chronic hypoxia. Moreover, NBP of 120 and 240 mg/kg significantly increased the average time of passive escape under acute and chronic hypoxia. These results suggested that NBP could improve physical and cognitive functions under acute and chronic hypobaric hypoxia. Furthermore, the levels of MDA and H2O2 decreased but those of SOD and GSH-Px increased under acute and chronic hypoxia. Furthermore, the content of ATP significantly increased, while lactate level significantly decreased. The results presented that NBP could regulate redox homeostasis and improve energy metabolism.Conclusion: NBP could improve physical and cognitive functions under acute and chronic hypobaric hypoxia by increasing anti-oxidative capacity and energy supply.

Help or Flight? Increased threat imminence promotes defensive helping in humans

Defensive responses to threatening situations vary with threat imminence, but it is unknown how those responses affect decisions to help others. Here, we manipulated threat imminence to investigate the impact of different defensive states on helping behaviour. Ninety-eight participants made trial-by-trial decisions about whether to help a co-participant avoid an aversive shock, at the risk of receiving a shock themselves. Helping decisions were prompted under imminent or distal threat, based on temporal distance to the moment of shock administration to the co-participant. Results showed that, regardless of how likely participants were to also receive a shock, they helped the co-participant more under imminent than distal threat. Individual differences in empathic concern were specifically correlated with helping during imminent threats. These results suggest defensive states driving active escape from immediate danger also facilitate decisions to help others, potentially by engaging neurocognitive systems implicated in caregiving across mammals.