孤束核神经元α肾上腺素能受体与5-羟色胺能受体的关系

在30个大鼠脑薄片上,共观察了5-HT与NE对57个孤束核神经元单位放电的作用。其中47个对5-HT与NE均有反应,而其中的8个用低钙高镁阻断突触传递后再给5-HT与NE仍有5例有该反应。另外5例对5-HT与NE单独起反应或均无反应的神经元用上述方法阻断突触传递后,有3例对5-HT与NE均有反应,提示在孤束核神经元上自身同时存在着5-HT与α肾上腺素受体。并有少数受其他神经元的抑制。在另外的5个NE与5-HT均兴奋的神经元,同时给NE与5-HT。其中3个转变为抑制;3个对单独用NE与5-HT抑制的神经元合用后,2个变为兴奋。提示在某些孤束核神经元上这两种受体可能存在相互抑制作用。

Effects of 5-HT and Norepinephrine on the Neuronal Activities of the Nucleus Tractus Solitaril in Medullary Slices

The relationship between 5-HT receptor and a-adrenoceptor was investigated in rat medullary slice preparations. In 57 nucleus tractus solitarii (NTS) neurons, 47 (82.5%) responded to both serotonin (5-HT) and norepinephrine (NE). After synapse transmission was blocked by perfusion of artificial cerebrospinal fluid (ACSF) with low calcium and high magnesium, 5 in 8 neurons were still sensitive to both 5-HT and NE. On the other hand, 3 in 5 neurons responding only to 5-HT or NA were sensitive to both 5-HT and NE after the synapse transmission blockage. In some neurons which exhibited excitatory or inhibitory responses to 5-HT or NE alone, the responses were inversed when perfused with 5-HT and NE in combination. These results suggest that there may exist an inhibitory interaction between 5-HT receptors and a-adrenoceptors in NTS and that most 5-NT and a-adrenoceptors coexist in the same NTS neurons.