AbstractBackgroundThe endocannabinoid system is present in multiple organ systems and is involved in smooth muscle regulation, immune function, neuroendocrine modulation and metabolism of tissues. Limited data are available regarding the presence and role of this system in reproductive tissues. Components of the endocannabinoid system have been identified in myometrial and placental tissues. However, no study has investigated differential expression of the endocannabinoid system in labor.ObjectivesThe purpose of this study was to identify and quantify two components of the endocannabinoid system, the CB1 cannabinoid receptor and cannabinoid receptor interacting protein 1a, in uterine and placental tissues, and to determine if there is differential expression in tissues exposed to labor. We hypothesized that CB1 cannabinoid receptor concentration would be altered in uterine and placental tissue exposed to labor as compared to tissues not exposed to labor.Study DesignUterine and placental tissue samples were collected in nine laboring and 11 non-laboring women undergoing cesarean delivery. CB1 cannabinoid receptor and cannabinoid receptor interacting protein 1a presence and quantification were evaluated using western blot and real-time quantitative polymerase chain reaction. Statistical comparisons of laboring and non-laboring subjects were made for uterine and placental tissue using a Mann-Whitney test.ResultsThe protein abundance of CB1 cannabinoid receptor in uterine tissue was significantly lower in tissues exposed to labor (p = 0.01). The protein abundance of cannabinoid receptor interacting protein 1a was lower in uterine tissue exposed to labor but did not reach statistical significance (p = 0.06). mRNA expression of CB1 cannabinoid receptor (p = 0.20) and cannabinoid receptor interacting protein 1a (p = 0.63) did not differ in labored compared to non-labored uterine tissues.ConclusionsOur findings of diminished protein density of CB1 cannabinoid receptor in uterine tissue exposed to labor support the hypothesis that the endocannabinoid system plays a role in parturition. Our data add to the growing body of evidence indicating the endocannabinoid system is of importance for successful reproduction and support the need for additional research investigating this complex system as it pertains to labor.
Differential Expression of CB1 Cannabinoid Receptor and Cannabinoid Receptor Interacting Protein 1a in Labor
