沙鼠前脑缺血后[3H]-PK 11195和[3H]-8-羟基二丙胺基四氢萘结合的变化

Changes in [3H]-PK 11195 and [3H]-8-OH-DPAT binding following forebrain ischaemia in the gerbil.

作者信息

Kenny B A, MacKinnon A C, Spedding M, Brown C M

机构信息

Department of Pharmacology, Syntex Research Centre, Heriot-Watt University Research Park, Riccarton, Edinburgh.

出版信息

Br J Pharmacol. 1993 Jun;109(2):437-42. doi: 10.1111/j.1476-5381.1993.tb13588.x.

DOI:10.1111/j.1476-5381.1993.tb13588.x

PMID:8395288

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC2175675/

Abstract

A high density of [3H]-PK 11195 binding sites was present in gerbil cortical membranes (Bmax [3H]-PK 11195 1360 +/- 71 fmol mg-1 protein) in comparison to rat cortical membranes (254 +/- 21 fmol mg-1 protein). This effect was species-specific as similar findings were obtained with hippocampal membranes (Bmax 1430 +/- 111 fmol mg-1 protein in gerbil, compared to 196 +/- 31 in rat). 2. RO 5-4864, also a peripheral type benzodiazepine compound, displayed low affinity for the [3H]-PK 11195 site in the gerbil (pKi 6.57 +/- 0.02 and 6.70 +/- 0.12 in hippocampus and cortex respectively) compared to rat (pKi 8.16 +/- 0.07 and 8.48 +/- 0.02). Central benzodiazepine compounds, diazepam and flunitrazepam, also displayed this trend. 3. RO 5-4864 displaced [3H]-PK 11195 binding from gerbil and rat cortical membranes through a competitive interaction with Hill slopes close to unity. In both tissues, saturation isotherms of [3H]-PK 11195 binding indicated that the presence of RO 5-4864 caused changes in Kd without any effect on Bmax. In kinetic experiments, the presence of RO 5-4864 failed to modify the rate of dissociation of [3H]-PK 11195 from equilibrium in both rat and gerbil cortical membranes. 4. Forebrain ischaemia in the Mongolian gerbil (5 min bilateral carotid artery occlusion) with 7 days recovery caused a significant (P<0.05) decrease in the density of hippocampal 5-HTlA binding sites labelled by [3H]-8-OH-DPAT (Bmax control, 393 +/- 33 fmol mg-1 protein; ischaemic, 289 +/- 21 fmol mg protein)and an increase (P<0.01) in [3H]-PK 11195 binding sites (Bmax control, 1430 +/- 111 fmol mg-1 protein; ischaemic, 2160 +/- 170 fmol mg-1 protein). Ischaemia and recovery had no effect on the affinity of either ligand.5. Autoradiography experiments in gerbil brain sections revealed that the ischaemia-induced increase in[3H]-PK 11195 binding was consistent and significant in the CA, subfield on the hippocampus (control,152 +/- 42 fmol mg-1 tissue; ischaemic, 314 +/- 43 fmol mg-1 tissue).

摘要

与大鼠皮质膜（254±21 fmol mg⁻¹蛋白质）相比，沙鼠皮质膜中存在高密度的[³H]-PK 11195结合位点（[³H]-PK 11195的Bmax为1360±71 fmol mg⁻¹蛋白质）。这种效应具有物种特异性，因为在海马体膜中也获得了类似的结果（沙鼠的Bmax为1430±111 fmol mg⁻¹蛋白质，而大鼠为196±31 fmol mg⁻¹蛋白质）。2. RO 5-4864也是一种外周型苯二氮䓬类化合物，与大鼠相比，它对沙鼠[³H]-PK 11195位点的亲和力较低（海马体和皮质中的pKi分别为6.57±0.02和6.70±0.12）（大鼠的pKi为8.16±0.07和8.48±0.02）。中枢苯二氮䓬类化合物地西泮和氟硝西泮也呈现出这种趋势。3. RO 5-4864通过与接近1的希尔斜率的竞争性相互作用，从沙鼠和大鼠皮质膜中取代[³H]-PK 11195结合。在两种组织中，[³H]-PK 11195结合的饱和等温线表明，RO 5-4864的存在导致Kd发生变化，但对Bmax没有影响。在动力学实验中，RO 5-4864的存在未能改变[³H]-PK 11195在大鼠和沙鼠皮质膜中从平衡状态解离的速率。4. 蒙古沙鼠前脑缺血（双侧颈总动脉闭塞5分钟）并恢复7天，导致海马体中由[³H]-8-OH-DPAT标记的5-HTlA结合位点密度显著降低（P<0.05）（对照的Bmax为393±33 fmol mg⁻¹蛋白质；缺血后的为289±21 fmol mg蛋白质），而[³H]-PK 11195结合位点增加（P<0.01）（对照的Bmax为1430±111 fmol mg⁻¹蛋白质；缺血后的为2160±170 fmol mg⁻¹蛋白质）。缺血和恢复对两种配体的亲和力均无影响。5. 沙鼠脑切片的放射自显影实验表明，缺血诱导的[³H]-PK 11195结合增加在海马体CA子区域是一致且显著的（对照为152±42 fmol mg⁻¹组织；缺血后为314±43 fmol mg⁻¹组织）。