Comparison of firing patterns in oxytocin- and vasopressin-releasing neurones during progressive dehydration
Comparison of firing patterns in oxytocin- and vasopressin-releasing neurones during progressive dehydration
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DOI：
10.1016/0006-8993(78)90730-8
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发表时间：
1978-06
期刊：
影响因子：
2.9
通讯作者：
Releasing Neurones;D. U. R. I. N. G. Progressive;N. Dehydratio;J. Wakerley;D. Poulain;D. Brown
中科院分区：
文献类型：
--
作者：
Releasing Neurones;D. U. R. I. N. G. Progressive;N. Dehydratio;J. Wakerley;D. Poulain;D. Brown
在麻醉的哺乳期大鼠上丘脑视上核内，观察了不同时间（0-24 h）的水剥夺对神经分泌细胞电活动的影响。视上单位被确定为逆向激活后刺激神经垂体，并根据其反应在反射性排乳分类为催产素或加压素细胞。在65加压素细胞，脱水增加了平均放电率从2.1尖峰/秒在0小时到6.8尖峰/秒在24小时，并导致从缓慢不规则的阶段性放电模式的变化。因此，脱水6小时或更长时间后，84-100%的加压素细胞呈阶段性放电，而正常条件下这一比例为12%。在相加压素细胞中，爆发内放电率与脱水阶段密切相关，从6 h的平均6.3峰/秒上升到24 h的12.0峰/秒。然而，没有系统的关系，观察脱水的阶段和平均爆发或沉默持续时间之间。在77个确定的催产素单位，脱水增加放电率从0.9尖峰/秒至2.8尖峰/秒后24小时，但只有3（4%）的细胞显示相位放电。相反，催产素单位从缓慢的不规则到快速的连续放电。总之，加压素和催产素神经元在慢性脱水过程中被激活，但它们的反应模式有显着差异。加压素细胞的阶段性放电可能在增加短峰间间期的发生从而促进激素释放方面很重要。
The electrical activity of neurosecretory cells in the supraoptic nucleus of the urethane-anaesthetized lactating rat was examined after periods of water deprivation ranging from 0–24 h. Supraoptic units were identified by antidromic activation following stimulation of the neurohypophysis, and classified as oxytocin or vasopressin cells according to their response during reflex milk ejection. In 65 vasopressin cells, dehydration increased the mean firing rate from 2.1 spikes/sec at 0 h to 6.8 spikes/sec at 24 h and caused a change from a slow irregular to a phasic firing pattern. Thus, after 6 h or more of dehydration, 84–100% of the vasopressin cells fired phasically, compared to 12% under normal conditions. In phasic vasopressin cells, the intraburst firing rates were closely related to the stages of dehydration, rising from a mean of 6.3 spikes/sec at 6 h to 12.0 spikes/sec at 24 h. However, no systematic relationship was observed between the stages of dehydration and the mean burst or silence durations. In 77 identified oxytocin units, dehydration increased the firing rate from 0.9 spikes/sec to 2.8 spikes/sec after 24 h, but only 3 (4%) of the cells showed phasic firing. Instead, the oxytocin units changed from a slow irregular to a fast continuus discharge.In conclusion, both vasopressin and oxytocin neurones are activated during chronic dehydration, but there is a marked difference in the pattern of their response. The phasic firing of the vasopressin cells may be important in increasing the occurrence of short interspike intervals and thus facilitating hormone release.