INFLUENCE OF AMBIENT TEMPERATURE ON THERMOREGULATORY RESPONSES TO 5-HYDROXYTRYPTAMINE, NORADRENALINE AND ACETYLCHOLINE INJECTED INTO LATERAL CEREBRAL VENTRICLES OF SHEEP, GOATS AND RABBITS
INFLUENCE OF AMBIENT TEMPERATURE ON THERMOREGULATORY RESPONSES TO 5-HYDROXYTRYPTAMINE, NORADRENALINE AND ACETYLCHOLINE INJECTED INTO LATERAL CEREBRAL VENTRICLES OF SHEEP, GOATS AND RABBITS
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DOI：
10.1113/jphysiol.1971.sp009330
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发表时间：
1971-01-01
影响因子：
5.5
通讯作者：
MASKREY, M
中科院分区：
文献类型：
--
作者：
BLIGH, J;COTTLE, WH;MASKREY, M
1. 环境温度 (Ta) 对体温调节效应器活动的影响以及向绵羊、山羊和兔子脑室内注射 5-羟色胺 (5-HT)、去甲肾上腺素 (NA)、乙酰胆碱 (ACh)、卡巴胆碱和七叶碱的体温 (Tb) 的影响，已通过温度传感器和温度调节效应器之间通路的简单神经元模型进行了解释。2.在所有三个物种中，最小剂量的 5-HT 都会导致呼吸频率 (RF) 上升和 Tbat highTa 下降，以及 EMG 活性降低和 Tbat lowTa 下降。这些效应可以解释为兴奋性递质作用于温暖受体的效应——热损失途径。3．在所有三个物种中，NA 导致 RF 降低和 Tbat highTa 升高，以及 EMG 活性降低和 Tbat lowTa 下降。这些效应被解释为抑制性递质同时作用于热传感器（热量损失途径）和冷传感器（热量产生途径）的效应。4．乙酰胆碱和拟胆碱物质卡巴胆碱和丝氨酸的作用很复杂，更难以解释。在小剂量下，对绵羊和山羊的影响是对冷传感器-产热途径的兴奋性递质的影响。 EMG 活动增加，Tbat lowTa 增加，RF 减少，Tbat highTa 增加。在山羊的较高剂量水平和兔子的所有剂量水平下，这些物质具有相反的作用，这归因于由于兴奋性物质过量而导致的突触阻滞。5．如果假设 (a) 在高和低环境温度下，对耳血管的直接热效应主导交感神经支配的热效应，并且 (b) 热传感器的影响是降低外周血管舒缩张力，而冷传感器的影响是增加外周血管舒缩张力，则环境温度和注射物质对耳温的影响与模型的预测一致。 6.得出的结论是，当考虑到热中性环境温度的物种差异以及兴奋性物质在高剂量水平下可能产生相反作用的可能性时，5-HT、NA和ACh在绵羊、山羊和兔子中控制体温的作用非常相似：5-HT对散热途径有兴奋性，ACh对产热途径有兴奋性，NA对这两种途径都有抑制作用。
1. The influences of ambient temperature (Ta) on the thermoregulatory effector activities and the body temperature (Tb) of intraventricular injections into the sheep, goat and rabbit of 5‐hydroxytryptamine (5‐HT), noradrenaline (NA), acetylcholine (ACh), carbachol and eserine, have been interpreted in terms of a simple neuronal model of the pathways between thermosensors and thermoregulatory effectors.2. In all three species 5‐HT in minimal doses caused a rise in respiratory frequency (RF) and a fall inTbat highTa, and a reduction in EMG activity and a fall inTbat lowTa. These effects could be interpreted as those of an excitatory transmitter acting on the warm receptor—heat loss pathway.3. In all three species NA caused a reduction in RF and a rise inTbat highTa, and a reduction in EMG activity and a fall inTbat lowTa. These effects are interpreted as those of an inhibitory transmitter acting both on the warm sensor—heat loss pathways and on the cold sensor—heat production pathway.4. The effects of ACh and the cholinomimetic substances carbachol and eserine are complex and more difficult to interpret. In small doses the effects on the sheep and goat are those of an excitatory transmitter on the cold sensor—heat production pathway. There was an increase in EMG activity and a rise inTbat lowTa, and a reduction in RF and a rise inTbat highTa. At higher dose levels in the goat and at all dose levels in the rabbit these substances had the reverse effects which are attributed to a synaptic block due to the excess of the excitatory substance.5. The effects of ambient temperature and injected substances upon ear temperature are consistent with the predictions of the model if it is assumed (a) that at high and low ambient temperatures direct thermal effects on ear vessels dominate those of the sympathetic innervation, and (b) that the warm sensor influence is to lower peripheral vasomotor tone, and the cold sensor influence is to increase it.6. The conclusion reached is that when consideration is given to species differences in the thermoneutral ambient temperature and to the possibility that excitatory substances have reversed effects at high dose levels, the effects of 5‐HT, NA and ACh in the control of body temperature are very similar in the sheep, goat and rabbit: 5‐HT is excitatory on the heat loss pathway, ACh is excitatory on the heat production pathway and NA has an inhibitory influence on both pathways.