| Title: | Selective G protein beta gamma-subunit compositions mediate phospholipase C activation in the vomeronasal organ |
| Author(s): | Runnenburger K; Breer H; Boekhoff I; |
| Address: | "Department of Pharmacology and Toxicology, University of Ulm, Germany" |
| ISSN/ISBN: | 0171-9335 (Print) 0171-9335 (Linking) |
| Abstract: | "Chemosensory neurons of the vomeronasal organ (VNO) are supposed to detect pheromones controlling social and reproductive behavior in most terrestrial vertebrates. Recent studies indicate that pheromone signaling in VNO neurons is mediated via phospholipase C (PLC) activation generating the two second messengers inositol-1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). Since G alpha(i) and G alpha(o) predominantly expressed in VNO neurons are usually not involved in activating PLC, it was explored if PLC activation may be mediated by G beta gamma subunits. It was found that a scavenger for beta gamma dimers reduced the urine-induced IP3 formation in VNO preparations in a dose-dependent manner indicating a role for G beta gamma complexes. Towards an identification of the relevant G beta and G gamma subunit(s), PCR approaches as well as immunohistochemical experiments were performed. It was found that out of the five known G beta subtypes, only G beta2 was expressed in both G alpha(i) as well as G alpha(o) neurons. Experimental approaches focusing on the spatial expression profile of identified G gamma subtypes revealed that G gamma8-positive neurons are preferentially localized to the basal region of the vomeronasal epithelium, whereas G gamma2-reactive cells are restricted to the apical G alpha(i)-positive layer of the sensory epithelium. As IP3 formation induced upon stimulation with volatile urinary compounds was selectively blocked by G gamma2-specific antibodies whereas second messenger formation elicited upon stimulation with alpha2u globulin was inhibited by antibodies recognizing G gamma8, it is conceivable that PLC activation in the two populations of chemosensory VNO neurons is mediated by different G beta gamma complexes" |
| Keywords: | "Animals Cell Membrane/drug effects/metabolism Chemoreceptor Cells/cytology/drug effects/*enzymology Dose-Response Relationship, Drug Female Heterotrimeric GTP-Binding Proteins/genetics/*metabolism Immunohistochemistry Inositol 1, 4, 5-Trisphosphate/metaboli;" |
| Notes: | "MedlineRunnenburger, Karin Breer, Heinz Boekhoff, Ingrid eng Research Support, Non-U.S. Gov't Germany 2002/11/20 Eur J Cell Biol. 2002 Oct; 81(10):539-47. doi: 10.1078/0171-9335-00277" |
