Department of Integrative Biology and Pharmacology, University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX 77030, USA.
J Exp Biol. 2011 Oct 1;214(Pt 19):3173-85. doi: 10.1242/jeb.058131.
Survivable injuries are a common yet costly experience. The ability to sense and respond to noxious stimuli is an almost universal trait, and prolonged behavioral alterations, including sensitization to touch and other stimuli, may function to ameliorate fitness costs associated with injury. Cephalopods can modify their behavior by learned association with noxious electric shock, but non-associative alterations of behavioral responses after tissue injury have not been studied. The aim of this study was to make the first systematic investigations in any cephalopod of behavioral responses and alterations elicited by explicit, minor injury. By testing responsiveness in the longfin squid, Loligo pealeii, to the approach and contact of an innocuous filament applied to different parts of the body both before and after injury to the distal third of one arm, we show that a cephalopod expresses behavioral alterations persisting for at least 2 days after injury. These alterations parallel forms of nociceptive plasticity in other animals, including general and site-specific sensitization to tactile stimuli. A novel finding is that hyper-responsiveness after injury extends to visual stimuli. Injured squid are more likely to employ crypsis than escape in response to an approaching visual stimulus shortly after injury, but initiate escape earlier and continue escape behaviors for longer when tested from 1 to 48 h after injury. Injury failed to elicit overt wound-directed behavior (e.g. grooming) or change hunting success. Our results show that long-lasting nociceptive sensitization occurs in cephalopods, and suggest that it may function to reduce predation risk after injury.
可存活的伤害是一种常见但代价高昂的现象。感知和应对有害刺激的能力是几乎普遍存在的特征，而长时间的行为改变，包括对触摸和其他刺激的敏感化，可能有助于减轻与伤害相关的适应成本。头足类动物可以通过与有害电击的学习关联来改变它们的行为，但尚未研究过组织损伤后行为反应的非联想改变。本研究的目的是对头足类动物进行首次系统研究，以了解明确的轻微损伤引起的行为反应和改变。通过测试长鳍鱿鱼 Loligo pealeii 在身体不同部位受到无害细丝接近和接触时的反应，我们发现头足类动物在受伤后至少 2 天内表现出持续的行为改变。这些改变与其他动物的疼痛可塑性形式相似，包括对触觉刺激的一般性和特定部位敏感化。一个新的发现是，受伤后会出现对视觉刺激的过度反应。受伤的鱿鱼在受伤后不久，对接近的视觉刺激更有可能采用伪装而不是逃避，但是在受伤后 1 到 48 小时进行测试时，它们会更早地开始逃避，并持续更长时间的逃避行为。受伤并没有引起明显的伤口导向行为（例如梳理）或改变狩猎成功率。我们的结果表明，头足类动物中存在持久的疼痛敏感化，这表明它可能有助于减少受伤后的捕食风险。
