Bicego Kenia C, Branco Luiz G S
Department of Physiology, Dental School of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil.
J Exp Biol. 2002 Nov;205(Pt 22):3513-8. doi: 10.1242/jeb.205.22.3513.
The preoptic area (POA) plays an important role in fever in mammals, but the role of this region in fever in ectothermic vertebrates has never been assessed. Toads, like all ectotherms, regulate their body temperature (T(b)) primarily by behavior and develop behavioral fever when injected with lipopolysaccharide (LPS). Therefore, we tested the hypothesis that the POA plays a role in the behavioral fever induced by LPS in the toad Bufo paracnemis. We made electrolytic lesions in the POA of toads (0.3 mA, 8 s) and measured preferred T(b) using a thermal gradient. After a period of 24h inside the gradient chamber, control, sham-operated and lesioned toads were systemically injected with LPS (200 micro g kg(-1)) or pyrogen-free saline. There was no significant effect of POA lesion in animals at their normal preferred T(b). LPS caused a significant increase in preferred T(b) of control and sham-operated toads, but lesions in the POA abolished this response. These results indicate that the POA is an important site in the central nervous system of toads, and perhaps of all vertebrates, involved in the development of fever.
视前区（POA）在哺乳动物发热过程中发挥着重要作用，但该区域在变温脊椎动物发热中的作用从未被评估过。蟾蜍与所有变温动物一样，主要通过行为来调节体温（Tb），并且在注射脂多糖（LPS）后会出现行为性发热。因此，我们检验了这样一个假设，即视前区在蟾蜍（Bufo paracnemis）中由LPS诱导的行为性发热中发挥作用。我们对蟾蜍的视前区进行了电解损伤（0.3 mA，8 s），并使用热梯度来测量偏好体温（Tb）。在梯度室中放置24小时后，对对照组、假手术组和损伤组蟾蜍全身注射LPS（200 μg kg-1）或无热原盐水。在处于正常偏好体温（Tb）的动物中，视前区损伤没有显著影响。LPS导致对照组和假手术组蟾蜍的偏好体温（Tb）显著升高，但视前区损伤消除了这种反应。这些结果表明，视前区是蟾蜍中枢神经系统中一个重要部位，可能也是所有脊椎动物中枢神经系统中参与发热产生的重要部位。
