Shen K Z, North R A
Vollum Institute, Oregon Health Sciences University, Portland 97201.
J Neurosci. 1993 Mar;13(3):894-9. doi: 10.1523/JNEUROSCI.13-03-00894.1993.
ATP and several congeners were applied to locus coeruleus neurons in slices cut from rat pons. Whole-cell recording of membrane current showed that ATP caused an inward current at -60 mV. Effective concentrations (applied by superfusion) were 3-300 microM, and the peak current was about 150 pA at -60 mV. 2-Methylthioadenosine 5'-triphosphate was slightly more potent than ATP, adenosine 5'-diphosphate was about equipotent with ATP, alpha,beta-methylene adenosine 5'-triphosphate was slightly less potent than ATP, and beta,gamma'-methylene adenosine 5'-triphosphate and adenosine 5'-monophosphate had little or no effect. Adenosine (100 microM) caused small outward currents (40 pA). By changing the ionic composition of the pipette and extracellular solution, it was shown that the inward current resulted from both an increase in conductance to sodium ions and a reduction in conductance to potassium ions. It is concluded that rat locus coeruleus neurons express P2 purinoceptors, activation of which depolarizes the cells predominantly by increasing a conductance that allows sodium ions to enter the cell.
将三磷酸腺苷（ATP）及其几种同系物应用于从大鼠脑桥切下的脑片蓝斑核神经元。对膜电流进行全细胞记录显示，ATP在-60 mV时引起内向电流。有效浓度（通过灌流施加）为3 - 300微摩尔，在-60 mV时峰值电流约为150皮安。2 - 甲硫基腺苷5'-三磷酸比ATP稍强，腺苷5'-二磷酸与ATP效力相当，α,β-亚甲基腺苷5'-三磷酸比ATP稍弱，而β,γ'-亚甲基腺苷5'-三磷酸和腺苷5'-单磷酸几乎没有作用。腺苷（100微摩尔）引起小的外向电流（40皮安）。通过改变微电极内和细胞外溶液的离子组成，表明内向电流是由于对钠离子的电导增加和对钾离子的电导降低所致。结论是大鼠蓝斑核神经元表达P2嘌呤受体，其激活主要通过增加允许钠离子进入细胞的电导使细胞去极化。
