title: L-arginine promotes capacitation and acrosome reaction in cryopreserved bovine spermatozoa.
abstract: Sperm capacitation and acrosome reaction are essential for fertilization and they are considered as part of an oxidative process involving superoxide and hydrogen peroxide. In human spermatozoa, the amino acid L-arginine is a substrate for the nitric oxide synthase (NOS) producing nitric oxide (NO*), a reactive molecule that participates in capacitation as well as in acrosome reaction. L-arginine plays an important role in the physiology of spermatozoa and has been shown to enhance their metabolism and maintain their motility. Moreover, L-arginine has a protective effect on spermatozoa against the sperm plasma membrane lipid peroxidation. In this paper, we have presented, for the first time, the effect of L-arginine on cryopreserved bovine sperm capacitation and acrosome reaction and the possible participation of NOS in both processes. Frozen-thawed bovine spermatozoa have been incubated in TALP medium with different concentrations of L-arginine and the percentages of capacitated and acrosome reacted spermatozoa have been determined. L-arginine induced both capacitation and acrosome reaction. NO* produced by L-arginine has been inhibited or inactivated using NOS inhibitors or NO* scavengers in the incubation medium, respectively. Thus, the effect of NOS inhibitors and NO* scavengers in capacitated and non-capacitated spermatozoa treated with L-arginine has also been monitored. The data presented suggest the participation of NO*, produced by a sperm NOS, in cryopreseved bovine sperm capacitation and acrosome reaction.
authors.affiliation: Biochemistry Area, School of Veterinary Sciences, University of Buenos Aires, Av. Chorroarín 280 (C1427CWO) Buenos Aires, Argentina. coflaher@yahoo.com
authors.forename: Cristian
authors.initials: C
authors.lastname: O'Flaherty
authors.forename: Pablo
authors.initials: P
authors.lastname: Rodriguez
authors.forename: Sudha
authors.initials: S
authors.lastname: Srivastava
mesh_terms: D020101:Acrosome Reaction / Q000502:physiology*; D000818:Animals; D001120:Arginine / Q000494:pharmacology*; D002417:Cattle; D002470:Cell Survival; D015925:Cryopreservation; D016166:Free Radical Scavengers / Q000378:metabolism; D006801:Humans; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D010084:Oxidation-Reduction; D013075:Sperm Capacitation / Q000502:physiology*; D013081:Sperm Motility / Q000502:physiology; D013094:Spermatozoa / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*
chemical_list: D016166:Free Radical Scavengers; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase