Arnauld E, Dufy B, Vincent J D
Brain Res. 1975 Dec 19;100(2):315-25. doi: 10.1016/0006-8993(75)90485-0.
Extracellularly recorded action potentials were obtained from hypothalamic supraoptic neurones in unanaesthetized rhesus monkeys. Rates and patterns of firing were studied during an initial control period, during 5 successive days of water deprivation and during 4 further days when drinking water was again available. During water deprivation, plasma osmolarity increased progressively from about 300 mOsmoles/kg to about 340 mOsmoles/kg; control values were again reached after 3 days of rehydration. Systematic changes in action potential firing accompanied the changes in plasma osmolarity. Under control conditions, the majority of cells fire slowly and irregularly (type i), whilst a few cells exhibited phases of alternating activity and silence (type p). As dehydration progresses, the frequency of neuronal firing increase and the pattern of firing changes. By the third day the majority of cells are type p with few type i cells being found. By the fourth day, the population consists of type p cells with some others showing a high continuous rate of firing (type c). By the fifth day, these two cell types are found in approximately equal proportions. Rehydration of the animal reverses the situation. We propose that type i cells contribute little, if at all, to hormone secretion, while type p and type c cells would be in a more actively secreting state. According to this view, the three firing patterns would represent different activity states of the same functional population stimulated by the unspecific stimulus of water deprivation rather than functionally different neurones. However, the use of stimuli which selectively release either oxytocin or vasopressin may be needed to answer this problem.
在未麻醉的恒河猴下丘脑视上核神经元中记录到细胞外动作电位。在初始对照期、连续5天禁水期间以及再次提供饮用水后的另外4天期间，研究了放电频率和模式。禁水期间，血浆渗透压从约300毫摩尔/千克逐渐升高至约340毫摩尔/千克；补液3天后恢复到对照值。动作电位放电的系统性变化伴随着血浆渗透压的变化。在对照条件下，大多数细胞放电缓慢且不规则（I型），而少数细胞表现出交替活动和静息的阶段（P型）。随着脱水进展，神经元放电频率增加且放电模式改变。到第三天，大多数细胞为P型，很少发现I型细胞。到第四天，群体由P型细胞组成，其他一些细胞表现出高持续放电率（C型）。到第五天，这两种细胞类型的比例大致相等。动物补液后情况逆转。我们提出I型细胞对激素分泌贡献很小（如果有贡献的话），而P型和C型细胞处于更活跃的分泌状态。根据这一观点，这三种放电模式代表了由禁水的非特异性刺激所刺激的同一功能群体的不同活动状态，而不是功能不同的神经元。然而，可能需要使用选择性释放催产素或血管加压素的刺激来回答这个问题。
