Basavarajappa B S, Hungund B L
New York State Psychiatric Institute at NKI, Orangeburg, New York 10962, USA.
J Neurosci Res. 2001 May 15;64(4):429-36. doi: 10.1002/jnr.1094.
The two inbred strains of mice C57BL/6 (alcohol-preferring) and DBA/2 (alcohol-avoiding) mice have been shown to differ significantly in their preference for alcohol (EtOH). We have previously demonstrated the differences in the density and the affinity of cannabinoid (CB1) receptors in the brains of the two inbred C57BL/6 and DBA/2 mouse strains. In the present study, we investigated the CB1 receptor agonist-stimulated guanosine-5'-O-(3-[(35)S]thio)-triphosphate ([(35)S]GTPgammaS) binding in plasma membranes (PM) from C57BL/6 and DBA/2 mice. The results indicate that the net CP55,940-stimulated [(35)S]GTPgammaS binding was increased with increasing concentrations of CB1 receptor agonists and GDP. The net CB1 receptor agonist (WIN55,212-2 or HU-210 or CP55,940)-stimulated [(35)S]GTPgammaS binding was reduced significantly (-10% to -12%, P < 0.05) in PM from DBA/2 mice; no significant differences were observed in basal [(35)S]GTPgammaS binding among these strains. Nonlinear regression analysis of net CP55,940-stimulated [(35)S]GTPgammaS binding showed that the B(max) of cannabinoid agonist-stimulated binding was significantly reduced (-24%) in DBA/2 mice (B(max) = 12.43 +/- 0.64 for C57BL/6 and 9.46 +/- 0.98 pmol/mg protein for DBA/2; P < 0.05) without any significant changes in the G protein affinity. The pharmacological specificity of CP55,940-stimulated [(35)S]GTPgammaS binding was examined with CB1 receptor antagonist SR141716A, and these studies indicated that CP55,940-stimulated [(35)S]GTPgammaS binding was blocked by SR141716A, with a decrease in the IC(50) values in the PM from the DBA/2 mouse strain. These results suggest that a signal transduction pathway(s) downstream from the CB1 receptor system may play an important role in controlling the voluntary EtOH consumption by these strains of mice.
两种近交系小鼠C57BL/6（偏好酒精）和DBA/2（回避酒精）对酒精（乙醇）的偏好存在显著差异。我们之前已经证明，这两种近交系C57BL/6和DBA/2小鼠大脑中大麻素（CB1）受体的密度和亲和力存在差异。在本研究中，我们研究了CB1受体激动剂刺激的鸟苷-5'-O-(3-[(35)S]硫代)-三磷酸（[(35)S]GTPγS）在C57BL/6和DBA/2小鼠质膜（PM）中的结合情况。结果表明，随着CB1受体激动剂和GDP浓度的增加，CP55,940刺激的[(35)S]GTPγS净结合增加。DBA/2小鼠质膜中CB1受体激动剂（WIN55,212-2或HU-210或CP55,940）刺激的[(35)S]GTPγS净结合显著降低（-10%至-12%，P<0.05）；这些品系之间的基础[(35)S]GTPγS结合未观察到显著差异。对CP55,940刺激的[(35)S]GTPγS净结合进行非线性回归分析表明，DBA/2小鼠中大麻素激动剂刺激结合的B(max)显著降低（-24%）（C57BL/6的B(max)=12.43±0.64，DBA/2的B(max)=9.46±0.98 pmol/mg蛋白；P<0.05），而G蛋白亲和力无任何显著变化。用CB1受体拮抗剂SR141716A检测了CP55,940刺激的[(35)S]GTPγS结合的药理学特异性，这些研究表明CP55,940刺激的[(35)S]GTPγS结合被SR141716A阻断，DBA/2小鼠品系质膜中的IC(50)值降低。这些结果表明，CB1受体系统下游的信号转导途径可能在控制这些品系小鼠的自愿乙醇消耗中起重要作用。
