Collins S M, Gardner J D
Am J Physiol. 1982 Dec;243(6):G497-504. doi: 10.1152/ajpgi.1982.243.6.G497.
Isolated smooth muscle cells were prepared from the fundus of guinea pig stomach by incubation with collagenase. Incubating the cells with the C-terminal octapeptide of cholecystokinin induced contraction, which was measured by micrometry and expressed as percent decrease in mean cell length. Cholecystokinin-induced contraction was maximal within 30 s and reduced cell length by approximately 37%. The threshold concentration of cholecystokinin was 0.1 pM, and the maximally effective concentration was 0.3 nM. Contraction caused by cholecystokinin could be inhibited by proglumide and by glucagon. Inhibition by proglumide was competitive and resulted in a parallel rightward shift of the cholecystokinin dose-response curve. In contrast, inhibition by glucagon was noncompetitive and resulted in a reduction in the efficacy of cholecystokinin without a change in its potency. Furthermore, proglumide-induced inhibition was specific for cholecystokinin, whereas glucagon-induced inhibition of contraction was nonspecific and reduced the contraction caused by carbamylcholine and the calcium ionophore A23187.
通过用胶原酶孵育从豚鼠胃底制备分离的平滑肌细胞。用胆囊收缩素的C末端八肽孵育细胞会诱导收缩，通过测微法测量并表示为平均细胞长度的减少百分比。胆囊收缩素诱导的收缩在30秒内达到最大值，使细胞长度减少约37%。胆囊收缩素的阈值浓度为0.1 pM，最大有效浓度为0.3 nM。胆囊收缩素引起的收缩可被丙谷胺和胰高血糖素抑制。丙谷胺的抑制是竞争性的，导致胆囊收缩素剂量反应曲线平行向右移动。相比之下，胰高血糖素的抑制是非竞争性的，导致胆囊收缩素的效力降低而其效能不变。此外，丙谷胺诱导的抑制对胆囊收缩素具有特异性，而胰高血糖素诱导的收缩抑制是非特异性的，可减少由氨甲酰胆碱和钙离子载体A23187引起的收缩。
