Robertson R M, Xu H, Shoemaker K L, Dawson-Scully K
Department of Biology, Queen's University, Kingston, Ontario, Canada.
J Neurobiol. 1996 Mar;29(3):367-83. doi: 10.1002/(SICI)1097-4695(199603)29:3<367::AID-NEU8>3.0.CO;2-7.
The natural habitat of the migratory locust, Locusta migratoria, is likely to result in locusts being heat stressed during their normal adult life. It is known that locusts exhibit a heat-shock response: exposure to 45 degrees C for 3 h induces thermotolerance and the expression of heat-shock proteins. We investigated the effects of exposure to heat-shock conditions on the thermosensitivity of flight rhythm generation in tethered, intact animals and in deafferented preparations. Heat shock had no effect on wingbeat frequency measured at the start of flight sequences, nor did it affect the postimaginal maturation of this parameter. During sustained flight, heat shock slowed the characteristic asymptotic reduction of wingbeat frequency. Wingbeat frequency of heat-shocked animals was less sensitive to temperature in the range 24 degrees to 47 degrees C than that of control animals, and the upper temperature limit, above which flight rhythms could not be produced, was 6 degrees to 7 degrees C higher in heat-shocked animals. These results were mirrored in the response of deafferented preparations, indicating that modifications in the properties of the flight neuromuscular system were involved in mediating the response of the intact animal. We propose that exposure to heat shock had the adaptive consequences of reducing thermosensitivity of the neural circuits in the flight system and allowing them to operate at higher temperatures.
飞蝗（Locusta migratoria）的自然栖息地可能导致蝗虫在正常成虫期遭受热应激。已知蝗虫会表现出热休克反应：暴露于45摄氏度3小时会诱导耐热性并促使热休克蛋白表达。我们研究了热休克条件对系留的完整动物以及去传入神经制备物中飞行节律产生的热敏感性的影响。热休克对飞行序列开始时测量的翅振频率没有影响，也不影响该参数的成虫后成熟过程。在持续飞行期间，热休克减缓了翅振频率典型的渐近式降低。热休克动物的翅振频率在24摄氏度至47摄氏度范围内对温度的敏感性低于对照动物，并且热休克动物中无法产生飞行节律的温度上限要高出6至7摄氏度。去传入神经制备物的反应也呈现出这些结果，表明飞行神经肌肉系统特性的改变参与介导了完整动物的反应。我们提出，暴露于热休克具有适应性后果，即降低飞行系统中神经回路的热敏感性，并使其能够在更高温度下运作。
