Is there a role for endocannabinoids in sperm–oviduct interaction?

The endocannabinoid system (ECS) has been found in reproductive cells and tissues in several mammals. Spermatozoa are able to respond to anandamide, and the oviduct is able to synthesize and modulate the concentration of this endocannabinoid along the isthmic and ampullary regions. The main aim of this study was to understand whether the ECS has a role during sperm storage and release within the oviduct in cattle. Data showed that 1) the endocannabinoid receptors 1 and 2 (CB1 and CB2) are present in bovine spermatozoa both in the initial ejaculate and in spermatozoa bound to the oviduct in vitro; 2) CB1 receptor is still detectable in spermatozoa released from the oviduct through penicillamine but not in those released through heparin; 3) arachidonylethanolamide (AEA) does not affect sperm viability, whereas it depresses sperm progressive motility and kinetic values; 4) sperm–oviduct binding and release in vitro are not influenced by AEA; 5) AEA depresses sperm–zona pellucida (ZP) binding; 6) binding of heparin-capacitated spermatozoa to the ZP is not affected by AEA; 7) N-acylphosphatidylethanolamine-selective phospholipase D, the main enzyme involved in anandamide synthesis, is expressed in oviductal epithelial cells. In conclusion, secretion of AEA from epithelial cells might contribute to the oviduct sperm-reservoir function, prolonging the sperm fertile life through the depression of motility and capacitation. Capacitation signals, such as heparin, that promote sperm release, might remodel the sperm surface and cause a loss of the sperm sensitivity to AEA

Cytogenetic analysis in Polypterus ornatipinnis (Actinopterygii, Cladistia, Polypteridae) and 5S rDNA

Polypteridae is a family of archaic freshwater African fish that constitute an interesting subject for the study of the karyological evolution in vertebrates, on account of their primitive morphological characters and peculiar relationships with lower Osteichthyans. In this paper, a cytogenetic analysis on twenty specimens of both sexes of Polypterus ornatipinnis the ornate “bichir”, coming from the Congo River basin, was performed by using both classical and molecular techniques. The karyotypic formula (2n = 36; FN = 72) was composed of 26 M + 10 SM. The Alu I banding, performed to characterize heterochromatin in this species, was mainly centromeric. Both the chromosome location of the ribosomal 5S and 18S rRNA genes were examined by using Ag-NOR, classical C-banding, CMA3 staining and FISH. CMA3 marked all centromerical regions and showed the presence of two GC rich regions on the p arm of the chromosome pair n°1 and on the q arm of the pair n°14. Staining with Ag-NOR marked the only telomeric region of the chromosome n°1 p arm. After PCR, the 5S rDNA in this species was cloned, sequenced and analyzed. In the 665 bp 5S rDNA sequence of P.ornatipinnis, a conserved 120 bp gene region for the 5S rDNA was identified, followed by a non-transcribed variable spacer (NTS) which included simple repeats, microsatellites and a fragment of a non-LTR retrotransposon R-TEX. FISH with 5S rDNA marked the subtelomeric region of the q arm of the chromosome pair n°14, previously marked by CMA3. FISH with 18S rDNA marked the telomeric region of the p arm of the pair n°1, previously marked both by Ag-NOR and CMA3. The (GATA)7 repeats marked the telomeric regions of all chromosome pairs, with the exclusion of the n°1, n°3 and n°14; hybridization with telomeric probes (TTAGGG)n showed signals at the end of all chromosomes. Karyotype evolution in Polypterus genus was finally discussed, including the new data obtained