title: Cholinergic receptors in the murine oviduct: inventory and coupling to intracellular calcium concentration.
abstract: OBJECTIVE
  In the oviduct, muscarinic acetylcholine receptors (MR) are linked with motility regulation and nicotinic receptors (nAChR) with ectopic pregnancy. We here aimed to determine the repertoire of cholinergic receptor expression in the murine oviduct and their functional coupling to regulation of intracellular calcium concentration ([Ca(2+)](i)).
  
  
  METHODS
  Cholinergic receptor transcripts were assessed by RT-PCR in oviductal segments (ampulla, isthmus, uterotubar junction) in all cyclic stages and pregnancy, and in laser-microdissected samples of epithelium and smooth muscle, nAChR subunit α3 distribution in tissue sections using an appropriate genetic reporter mouse strain. [Ca(2+)](i) responses were monitored in ciliated and non-ciliated oviductal cells isolated from wild-type and MR subtypes 1 and 3 gene deficient mice.
  
  
  RESULTS
  Transcripts for all MR subtypes (M1-M5) are constantly expressed whereas there is some variability in nAChR expression from individual to individual. The qualitative expression pattern is independent from the hormonal status of the animal, except for nAChR α7, which is less present during pregnancy. The epithelium expresses M1, M3, nAChR α7 (data from laser-assisted microdissection) and nAChR α3 (ultrastructural investigation of reporter mice). MR dominate over nAChR in increasing [Ca(2+)](i) with being M3 the major, but not sole subtype driving this effect. The general nAChR inhibitor mecamylamine enhances muscarinic and purinergic responses.
  
  
  CONCLUSIONS
  In conclusion, the murine oviduct is endowed with a multiplicity of muscarinic and nicotinic receptors subtypes that, with respect to regulation of [Ca(2+)](i), are inversely linked to each other. The major, but not sole, cholinergic receptor driving increase in [Ca(2+)](i) is M3.
authors.affiliation: Institute of Anatomy and Cell Biology, Justus-Liebig-University, 35385 Giessen, Germany. miriamwolff@web.de
authors.forename: Miriam
authors.initials: M
authors.lastname: Wolff
authors.forename: Katharina
authors.initials: K
authors.lastname: Noreikat
authors.forename: Ines
authors.initials: I
authors.lastname: Ibanez-Tallon
authors.forename: Katrin S
authors.initials: KS
authors.lastname: Lips
authors.forename: Sabine
authors.initials: S
authors.lastname: Kölle
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kummer
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D005187:Fallopian Tubes / Q000378:metabolism* / Q000648:ultrastructure; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D011247:Pregnancy; D011950:Receptors, Cholinergic / Q000032:analysis* / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic
chemical_list: D011950:Receptors, Cholinergic; D002118:Calcium