Mulder A H, van Amsterdam R G, Wilbrink M, Schoffelmeer A N
Department of Pharmacology, Free University, Medical Faculty Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.
Neurochem Int. 1983;5(3):291-7. doi: 10.1016/0197-0186(83)90031-1.
Brain slices obtained from neocortex, hypothalamus or hippocampus were incubated with [(3)H]histamine and subsequently superfused and exposed to different depolarizing stimuli, viz. high K(+)-concentrations, electrical field stimulation and veratrine. K(+)-induced release of tritium was completely calcium-dependent and its magnitude depended on the K(+)-concentration, with maximal release being reached at 56 mM K(+). Electrically-evoked release of tritium increased with increasing frequencies and reached its maximum at about 20 Hz. The electrically-evoked release appeared to be totally calcium-dependent and it was strongly inhibited by tetrodotoxin. Veratrine (5-100 ?M) also induced a release of tritium; maximal release was obtained at 100 ?M veratrine. Veratrine-induced release was partially calcium-dependent and was strongly reduced by tetrodotoxin. Taken together the data indicate that the depolarization-induced release of tritium from brain slices pre-labelled with [(3)H]histamine, represents [(3)H]histamine release from neurons and not from either mast cells or glial cells. It remains to be established whether these neurons are specifically histaminergic.
取自新皮层、下丘脑或海马体的脑片与[³H]组胺一起孵育，随后进行灌流并暴露于不同的去极化刺激，即高钾浓度、电场刺激和藜芦碱。钾离子诱导的氚释放完全依赖于钙，其释放量取决于钾离子浓度，在56 mM钾离子时达到最大释放量。电诱发的氚释放随频率增加而增加，在约20 Hz时达到最大值。电诱发的释放似乎完全依赖于钙，并且被河豚毒素强烈抑制。藜芦碱（5 - 100 μM）也诱导了氚的释放；在100 μM藜芦碱时获得最大释放量。藜芦碱诱导的释放部分依赖于钙，并被河豚毒素强烈减少。综合这些数据表明，用[³H]组胺预标记的脑片中去极化诱导的氚释放代表神经元释放的[³H]组胺，而非肥大细胞或神经胶质细胞释放的。这些神经元是否为特异性组胺能神经元还有待确定。
