Biological Center of Czech Academy of Sciences, Institute of Entomology, Drnovská 507, Prague 6, Czech Republic.
J Insect Physiol. 2012 Aug;58(8):1072-81. doi: 10.1016/j.jinsphys.2012.04.014. Epub 2012 May 16.
Recent electrocardiographic (ECG) studies of insect hearts revealed the presence of human-like, involuntary and purely myogenic hearts. Certain insects, like a small light-weight species of hoverfly (Episyrphus balteatus), have evolved a very efficient cardiac system comprised of a compact heart ventricle and a narrow tube of aorta, which evolved as an adaptation to sustained hovering flights. Application of thermocardiographic and optocardiographic ECG methods revealed that adult flies of this species use the compact muscular heart chamber (heart ventricle) for intensive pumping of insect "blood" (haemolymph) into the head and thorax which is ringed all over with indirect flight musculature. The recordings of these hearts revealed extremely high, record rates of forward-directed, anterograde heartbeat (up to 10Hz), associated with extremely enhanced synchronic (not peristaltic) propagation of systolic myocardial contractions (32.2mm/s at room temperature). The relatively slow, backward-directed or retrograde cardiac contractions occurred only sporadically in the form of individual or twinned pulses replacing occasionally the resting periods. The compact heart ventricle contained bi-directional lateral apertures, whose opening and closure diverted the intracardiac anterograde "blood" streams between the abdominal haemocoelic cavity and the aortan artery, respectively. The visceral organs of this flying machine (crop, midgut) exhibited myogenic, extracardiac peristaltic pulsations similar to heartbeat, including the periodically reversed forward and backward direction of the peristaltic waves. The tubular crop contracted with a periodicity of 1Hz, both forwards and backwards, with propagation of the peristaltic waves at 4.4mm/s. The air-inflated and blindly ended midgut contracted at 0.2Hz, with a 0.9mm/s propagation of the peristaltic contraction waves. The neurogenic system of extracardiac haemocoelic pulsations, widely engaged in the regulation of circulatory and respiratory functions in other insect species, has been replaced here by a more economic, myogenic pulsation of the visceral organs as a light-weight evolutionary adaptation to prolonged hovering flight. Striking structural, functional and even genetic similarities found between the hearts of Episyrphus, Drosophila and human hearts, have been practically utilised for inexpensive testing of new cardioactive or cardioinhibitory drugs on insect heart.
最近对昆虫心脏的心电图（ECG）研究表明，存在类似于人类的、无意识的和纯粹的心肌心脏。某些昆虫，如一种小型轻量级的悬停蝇（Episyrphus balteatus），已经进化出一种非常高效的心脏系统，由一个紧凑的心室和一个狭窄的主动脉管组成，这是对持续悬停飞行的适应。应用热心动描记法和光心动描记法 ECG 方法表明，该物种的成年蝇使用紧凑的心肌室（心室）将昆虫“血液”（血淋巴）强力泵入头部和胸部，胸部被间接飞行肌肉环绕。这些心脏的记录显示，向前指向的、顺行的心跳率极高（高达 10Hz），与心肌收缩的极度增强的同步（非蠕动）传播相关（在室温下为 32.2mm/s）。相对较慢的、向后指向的或逆行的心脏收缩仅偶尔以单个或成对脉冲的形式零星发生，偶尔取代休息期。紧凑的心室包含双向侧向开口，其开口和关闭分别将心内顺行“血液”流引导至腹部血腔和主动脉。这种飞行机器的内脏器官（胃、中肠）表现出类似于心跳的、心肌的、心外的蠕动搏动，包括蠕动波的周期性反向向前和向后方向。管状胃以 1Hz 的周期性向前和向后收缩，蠕动波的传播速度为 4.4mm/s。充气的和盲端的中肠以 0.2Hz 的频率收缩，蠕动收缩波的传播速度为 0.9mm/s。广泛参与其他昆虫物种循环和呼吸功能调节的心外血腔神经源性搏动系统已被更经济的、内脏器官的心肌搏动所取代，这是对长时间悬停飞行的轻量级进化适应。在 Episyrphus、 Drosophila 和人类心脏之间发现的惊人的结构、功能甚至遗传相似性，已被实际用于在昆虫心脏上廉价测试新的心脏活性或心脏抑制药物。
