Dumont M, Lemaire S
Department of Pharmacology, Faculty of Medicine, University of Ottawa, Ontario, Canada.
J Mol Cell Cardiol. 1993 Aug;25(8):983-91. doi: 10.1006/jmcc.1993.1110.
The binding characteristics of [3H]Dynorphin A-(1-13) ([3H]Dyn A-(1-13) were examined in membrane preparations of rat heart. Saturation binding studies with increasing concentrations between 2.5 and 500 nM indicated that [3H]Dyn A-(1-13) binds to a single population of sites with a Kd of 285 nM and a Bmax of 215 pmol/mg protein. [3H]Dyn A-(1-13) binding is sensitive to trypsin treatment and it is inhibited by Zn2+ and Mg2+ with IC50 values of 159 and 310 microM, respectively. Dyn A and related peptides competes with the binding of [3H]Dyn A-(1-13) with the following order of potency: Dyn A-(1-13) > Dyn A > Dyn B > alpha-neo-endorphin > Dyn A-(1-8). The non-opioid peptides Dyn A-(2-13), Dyn A-(3-13) and Dyn A-(5-13) are as potent (Ki of 0.35, 0.44 and 0.59 microM, respectively) as Dyn A-(1-13) (Ki of 0.36 microM) in inhibiting [3H]Dyn A-(1-13) binding while Leu-enkephalin (Leu-Enk) exhibits no inhibitory effect at 100 microM. Selective ligands for kappa (kappa: U-50,488H, U-69,593), mu (mu: [D-Ala2, MePhe4, Glyol5]Enk) and delta (delta: [D-Ser2, Thr6]Leu-Enk) opioid receptors as well as for phencyclidine (PCP: MK-801, TCP) and sigma (sigma: (+)-SKF-10047, DTG, 3(+)-PPP) receptors show little or no inhibition of [3H]Dyn A-(1-13) binding at 100 microM. These results indicate that the heart contains a low affinity high capacity binding site for Dyn A and related peptides, distinct from opioid, PCP and sigma receptors.
在大鼠心脏的膜制剂中检测了[3H]强啡肽A-(1-13)（[3H]Dyn A-(1-13)）的结合特性。用2.5至500 nM之间递增浓度进行的饱和结合研究表明，[3H]Dyn A-(1-13)与单一的位点群体结合，其解离常数（Kd）为285 nM，最大结合容量（Bmax）为215 pmol/mg蛋白质。[3H]Dyn A-(1-13)的结合对胰蛋白酶处理敏感，并且被Zn2+和Mg2+抑制，其半数抑制浓度（IC50）值分别为159和310 microM。强啡肽A及相关肽与[3H]Dyn A-(1-13)的结合竞争能力顺序如下：强啡肽A-(1-13)＞强啡肽A＞强啡肽B＞α-新内啡肽＞强啡肽A-(1-8)。非阿片肽强啡肽A-(2-13)、强啡肽A-(3-13)和强啡肽A-(5-13)在抑制[3H]Dyn A-(1-13)结合方面与强啡肽A-(1-13)效力相当（Ki分别为0.35、0.44和0.59 microM），而亮氨酸脑啡肽（Leu-Enk）在100 microM时无抑制作用。κ（κ：U-50,488H、U-69,593）、μ（μ：[D-Ala₂, MePhe₄, Glyol₅]脑啡肽）和δ（δ：[D-Ser₂, Thr₆]亮氨酸脑啡肽）阿片受体以及苯环己哌啶（PCP：MK-801、TCP）和σ（σ：(+)-SKF-10047、DTG、3(+)-PPP）受体的选择性配体在100 microM时对[3H]Dyn A-(1-13)结合几乎没有抑制作用。这些结果表明，心脏含有一个对强啡肽A及相关肽具有低亲和力、高容量的结合位点，与阿片、PCP和σ受体不同。
