Barr Stuart, Elwood Robert W
School of Biological Sciences, Queen's University, Belfast BT9 5DL, UK.
Animals (Basel). 2024 Jun 6;14(11):1705. doi: 10.3390/ani14111705.
Noxious chemicals, coupled with morphine treatment, are often used in studies on pain in vertebrates. Here we show that injection of morphine caused several behavioural changes in the crab, , including reduced pressing against the sides of the enclosure and more rubbing and picking at the mouth parts and, at least for a short time, more defensive displays. Subsequent injection of acetic acid into one rear leg caused rubbing of the injected leg and the injected leg was held vertically off the ground. These activities directed at or involving the specific leg are consistent with previous observations of directed behaviour following noxious stimuli and are consistent with the idea that decapods experience pain. Further, acetic acid but not injection of water induced autotomy of the injected leg in these animals. Because autotomy is temporally associated with directed behaviour, it is possible that the autotomy is a pain-related response. Acetic acid is clearly a noxious substance when applied to decapods. However, morphine had no effect on the activities associated with acetic acid injection and thus there is no evidence for an analgesic effect. Further, the injection of acetic acid did not interfere with behavioural effects of morphine. The activities directed towards the site of injection are like those observed with injection, or with external application, of various noxious substances and the present study adds to a growing body of knowledge about possible pain in decapods.
有毒化学物质与吗啡治疗相结合，常用于脊椎动物疼痛研究。在此我们表明，注射吗啡会使螃蟹出现多种行为变化，包括减少对饲养箱侧壁的挤压、更多地摩擦和搔抓口器部位，并且至少在短时间内会出现更多防御性展示。随后向一只后腿注射醋酸会导致该注射腿出现摩擦行为，且注射腿会垂直抬离地面。这些针对特定腿部或涉及该腿部的活动与先前关于有害刺激后定向行为的观察结果一致，并且与十足目动物会经历疼痛这一观点相符。此外，在这些动物中，注射醋酸而非注射水会导致注射腿自切。由于自切在时间上与定向行为相关，所以自切有可能是一种与疼痛相关的反应。醋酸应用于十足目动物时显然是一种有害物质。然而，吗啡对与醋酸注射相关的活动没有影响，因此没有证据表明其具有镇痛作用。此外，注射醋酸并未干扰吗啡的行为效应。针对注射部位的活动与注射或外用各种有害物质时观察到的活动相似，本研究为关于十足目动物可能存在疼痛的知识积累增添了内容。
