The caveolar rows colocalize with myofilaments bundles in peritubular myoid cells from adult rat

LOSINNO, ANTONELLA D; MORALES, ALFONSINA; AMAYA, M CELINA; COSTANTINO, V VALERIA; FERNÁNDEZ, DARIO; LOPEZ, LUIS A

Mendoza

Congreso; XLVIII Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular; 2012

Sociedad Argentina de Investigación Bioquímica y Biología Molecular

In the mammalian testis, peritubular myoid cells (PM cells) surround seminiferous tubules (ST) and participate in their contraction. PM cells contain myofilaments (MFs) arranged in two independent layers, the outer and the inner ones with longitudinal and transverse MFs to the ST axis. Endothelin-1 induces PM cells contraction by binding to its receptors (ETRs) localized in fixed caveolae. Due to the arrangements of MFs in PM cells, we asked if the localization of caveolae and ETRs receptors follow the MFs orientation. For this purpose, ST from adult rat testes were fixed with 4% paraformaldehyde for immunofluorescence (IF) or with 5% glutaraldehyde for transmission electron microscopy (TEM). For IF, MFs were visualized with anti-alpha actin antibody (Ab), caveolae using anti-caveolin-1 Ab, and ETRs with ETAR and ETBR Abs. By confocal microscopy, caveolin-1 and ETRs appear in the outer and the inner plasma membranes of PM cells in rows following the orientation of MFs bundles in the longitudinal and transverse layers respectively. By TEM we observed a close association of caveolae in the plasma membrane with the underneath Mfs. The conspicuous colocalization among the caveolar rows, ETRs in each plasma membrane and the MFs bundles reinforces the possibility that PM cells generate contractile force in two axes.