title: The cholinergic system in rat testis is of non-neuronal origin.
abstract: The cholinergic system consists of acetylcholine (ACh), its synthesising enzyme, choline acetyltransferase (CHAT), transporters such as the high-affinity choline transporter (SLC5A7; also known as ChT1), vesicular ACh transporter (SLC18A3; also known as VAChT), organic cation transporters (SLC22s; also known as OCTs), the nicotinic ACh receptors (CHRN; also known as nAChR) and muscarinic ACh receptors. The cholinergic system is not restricted to neurons but plays an important role in the structure and function of non-neuronal tissues such as epithelia and the immune system. Using molecular and immunohistochemical techniques, we show in this study that non-neuronal cells in the parenchyma of rat testis express mRNAs for Chat, Slc18a3, Slc5a7 and Slc22a2 as well as for the CHRN subunits in locations completely lacking any form of innervation, as demonstrated by the absence of protein gene product 9.5 labelling. We found differentially expressed mRNAs for eight α and three β subunits of CHRN in testis. Expression of the α7-subunit of CHRN was widespread in spermatogonia, spermatocytes within seminiferous tubules as well as within Sertoli cells. Spermatogonia and spermatocytes also expressed the α4-subunit of CHRN. The presence of ACh in testicular parenchyma (TP), capsule and isolated germ cells could be demonstrated by HPLC. Taken together, our results reveal the presence of a non-neuronal cholinergic system in rat TP suggesting a potentially important role for non-neuronal ACh and its receptors in germ cell differentiation.
authors.affiliation: Anatomy and Histology, FMST, Flinders University, Adelaide, South Australia, Australia.
authors.forename: S U
authors.initials: SU
authors.lastname: Schirmer
authors.forename: I
authors.initials: I
authors.lastname: Eckhardt
authors.forename: H
authors.initials: H
authors.lastname: Lau
authors.forename: J
authors.initials: J
authors.lastname: Klein
authors.forename: Y C
authors.initials: YC
authors.lastname: DeGraaf
authors.forename: K S
authors.initials: KS
authors.lastname: Lips
authors.forename: C
authors.initials: C
authors.lastname: Pineau
authors.forename: I L
authors.initials: IL
authors.lastname: Gibbins
authors.forename: W
authors.initials: W
authors.lastname: Kummer
authors.forename: A
authors.initials: A
authors.lastname: Meinhardt
authors.forename: R V
authors.initials: RV
authors.lastname: Haberberger
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D002795:Choline O-Acetyltransferase / Q000378:metabolism*; D059329:Cholinergic Neurons / Q000166:cytology / Q000378:metabolism; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D027701:Organic Cation Transport Proteins / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011920:Rats, Inbred WF; D011950:Receptors, Cholinergic / Q000235:genetics / Q000378:metabolism; D012708:Sertoli Cells / Q000166:cytology / Q000378:metabolism; D013091:Spermatogenesis; D013094:Spermatozoa / Q000166:cytology / Q000378:metabolism; D013737:Testis / Q000166:cytology / Q000294:innervation / Q000378:metabolism*; D050494:Vesicular Acetylcholine Transport Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D009419:Nerve Tissue Proteins; D027701:Organic Cation Transport Proteins; D020033:Protein Isoforms; D021122:Protein Subunits; D012333:RNA, Messenger; D011950:Receptors, Cholinergic; C493461:Slc18a3 protein, rat; D050494:Vesicular Acetylcholine Transport Proteins; D002795:Choline O-Acetyltransferase; D000109:Acetylcholine