Altered patterns of filopodia production in CHO cells heterologously expressing zebra finch CB₁cannabinoid receptors

Abstract

Abbreviations: CHO cells, Chinese hamster ovary cells; DMSO, dimethyl sulfoxide; M/C, membrane:cytoplasm; PBS, phosphate-buffered saline; SR, the CB 1 receptor-selective antagonist/inverse agonist SR141716A; WIN, the cannabinoid agonist WIN55212-2; zfCB1, zebra finch CB 1 cannabinoid receptorRecent findings indicate that cannabinoid-altered vocal development involves elevated densities of dendritic spines in a subset of brain regions involved in zebra finch song learning and production suggesting that cannabinoid receptor activation may regulate cell structure. Here we report that activation of zebra finch CB 1 receptors (zfCB 1 , delivered by a lentivector to CHO cells) produces dose-dependent biphasic effects on the mean length of filopodia expressed: Low agonist concentrations (3 nM WIN55212-2) increase lengths while higher concentrations reduce them. In contrast, treatment of zfCB 1 -expressing cells with the antagonist/inverse agonist SR141716A causes increases in both mean filopodia length and number at 30 and 100 nM. These results demonstrate that CB 1 receptor activation can differentially influence filiopodia elongation depending on dose, and demonstrate that manipulation of cannabinoid receptor activity is capable of modulating cell morphology.

Novel song-stimulated dendritic spine formation and Arc/Arg3.1 expression in zebra finch auditory telencephalon are disrupted by cannabinoid agonism

“…For example, Arc has been found to co-precipitate and share nearly identical intracellular distribution with F-actin in dendritic spines, and has been shown as a necessary component of actin-dependent morphological change (Bramham et al, 2008; Bramham et al, 2010; Guzowski et al, 2005; Lyford et al, 1995). Note that we have found, in vitro, that F-actin dynamics are altered following CB 1 activation (Soderstrom et al, 2012). Both Arc mRNA and protein sequences are highly conserved across vertebrates, and their expression during learning is so robust, distinct, and reproducible that it is used as an indicator of neural circuitry that underlies learning and memory (Guzowski et al, 2001; Guzowski et al, 2005).…”