title: Post-testicular changes in the density and distribution of intramembrane particles of stallion sperm surface domains.
abstract: Freeze-fracture replicas of stallion spermatozoa, collected from the proximal caput, corpus and cauda epididymides regions, were analyzed by electron microscopy to explore the distribution and density of intramembrane particles (IMP). Conspicuous differences in density and arrangement of the IMP were observed in the different topographical domains of mature and immature spermatozoa. A reduction of IMP, especially remarkable in the post-acrosomal domain, was observed in mature epididymal spermatozoa when compared with samples collected from ductuli efferentes. Some structural species-specific differences were also observed. The significance of these changes has not been determined, but remodeling of membrane components during developmental processes constitutes a fine control mechanism to ensure that key molecules are in the correct membrane position and during an appropriate timeframe to mediate fertilization.
authors.affiliation: Setor Biologia da Reprodução, Centro de Biociencias e Biotecnologia, Universidade Estadual do Norte Fluminense, Av. Alberto Lamêgo 2000, Parque Califórnia, CEP 28013-600, Campos dos Goytacazes, RJ, Brazil. mlopez@uenf.br <mlopez@uenf.br>
authors.forename: M L
authors.initials: ML
authors.lastname: López
authors.forename: N
authors.initials: N
authors.lastname: Olea
authors.forename: C A
authors.initials: CA
authors.lastname: Retamal
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000502:physiology / Q000648:ultrastructure*; D004822:Epididymis / Q000502:physiology*; D006736:Horses / Q000502:physiology*; D008297:Male; D013094:Spermatozoa / Q000502:physiology* / Q000648:ultrastructure*; D013737:Testis / Q000502:physiology*