Key molecules in the GABA signalling pathway are present in mouse and human cervical tissue.

Cervical mucus modulates fertility by cyclical changes of its biophysical and functional properties. Based on an analogy with bronchial goblet cells we set out to investigate the possible role of the gamma-aminobutyric acid (GABA) signalling pathway in the mediation of oestrogen-induced mucus secretion from endocervical secretory cells. The aim of the study was to examine the existence of GABAA receptor (GABAAR), glutamic acid decarboxylase 65/67 (GAD65/67) and vesicular GABA transporter (VGAT) in human and mouse cervical tissue. The mouse cervical tissue expressed GabaAR mRNA transcripts throughout the oestrous cycle. GABAAR-positive immunolabelling was present in the superficial layer of the mouse cervico-vaginal epithelium in pro-oestrus. Human cervical tissue showed the presence of GABAAR, GAD67 and VGAT mRNA transcripts and clear immunofluorescent signals of all three molecules were detected in the endocervical secretory epithelium. The results of this study confirmed that elements of the GABA signalling pathway are present in the secretory epithelium of mouse and human cervical tissue and that GABA signalling pathway could be considered a possible mediator in oestrogen regulation of mucus secretion in the endocervical glands.