Calvo J R, Montilla M L, Guerrero J M, Segura J J
Departamento de Bioquímica Médica y Biología Molecular, Facultad de Medicina, Universidad de Sevilla, Spain.
J Neuroimmunol. 1994 Feb;50(1):85-93. doi: 10.1016/0165-5728(94)90218-6.
Receptors for VIP in mouse peritoneal macrophages (MPM) were examined using [125I]labeled VIP as ligand. The receptor binding was rapid, reversible, saturable, specific, and dependent on time, pH, temperature and cell concentration. At 15 degrees C, the stoichiometric data suggested the presence of two classes of VIP receptors with Kd values of 1.05 +/- 0.2 and 66.4 +/- 11.0 nM and binding capacities of 19.2 +/- 2.8 and 706.6 +/- 172.0 fmol VIP/10(6) cells. The interaction showed a high degree of specificity, as suggested by competition experiments with various peptides structurally related to VIP as follows: VIP > helodermin > rGRF > PHI >> secretin. Glucagon, pancreastatin, somatostatin, insulin, and octapeptide of cholecystokinin (CCK 26-33) were ineffective at concentrations as high as 1 microM. VIP was a potent and efficient stimulator of cyclic AMP production in MPM. The stimulation was observed at a concentration as low as 0.01 nM VIP. Half-maximal stimulation (ED50) was observed at 1.0 +/- 0.2 nM VIP, and maximal stimulation (three-fold above basal levels) was obtained between 0.1-1 microM. The cyclic AMP system of mouse peritoneal macrophages showed a high specificity for VIP. The order of potency observed in inducing cyclic AMP production was VIP > helodermin > rGRF > PHI >> secretin. Glucagon, insulin, pancreastatin, somatostatin and octapeptide of cholecystokinin did not modify cyclic AMP levels at concentrations as high as 1 microM.(ABSTRACT TRUNCATED AT 250 WORDS)
使用[125I]标记的血管活性肠肽（VIP）作为配体，检测了小鼠腹腔巨噬细胞（MPM）中的VIP受体。受体结合迅速、可逆、可饱和、具有特异性，且依赖于时间、pH、温度和细胞浓度。在15℃时，化学计量学数据表明存在两类VIP受体，其解离常数（Kd）值分别为1.05±0.2和66.4±11.0 nM，结合容量分别为19.2±2.8和706.6±172.0 fmol VIP/10(6)细胞。如与各种结构上与VIP相关的肽进行竞争实验所示，这种相互作用表现出高度特异性，顺序如下：VIP＞蛙皮素＞大鼠生长激素释放因子＞胰高血糖素样肽I＞＞促胰液素。胰高血糖素、胰抑制素、生长抑素、胰岛素和胆囊收缩素八肽（CCK 26 - 33）在高达1μM的浓度下均无效。VIP是MPM中环磷酸腺苷（cAMP）产生的有效刺激剂。在低至0.01 nM VIP的浓度下即可观察到刺激作用。在1.0±0.2 nM VIP时观察到半数最大刺激（ED50），在0.1 - 1μM之间获得最大刺激（比基础水平高3倍）。小鼠腹腔巨噬细胞的cAMP系统对VIP具有高度特异性。在诱导cAMP产生中观察到的效力顺序为：VIP＞蛙皮素＞大鼠生长激素释放因子＞胰高血糖素样肽I＞＞促胰液素。胰高血糖素、胰岛素、胰抑制素、生长抑素和胆囊收缩素八肽在高达1μM的浓度下均未改变cAMP水平。（摘要截短于250字）
