title: Nitric oxide and fusion with prostasomes increase cytosolic calcium in progesterone-stimulated sperm.
abstract: Spermatozoa must undergo a number of reactions before they are able to fertilize the oocyte. Among these is the acrosome reaction, which is related to an increase in cytosolic Ca2+ concentration ([Ca2+]i). It has been reported in the literature that progesterone may achieve this effect through the intervention of extragenomic receptors. Nitric oxide (NO) has been reported to affect spermatozoa; the nature of the effect depends on the concentration of the radical. In a previous paper, we reported that the fusion of spermatozoa with prostasomes may also produce a transient increase in spermatozoa [Ca2+]i; in addition, this phenomenon causes a long-lasting effect that influences the action of progesterone. In this paper, we test the effects of a NO donor (CysNO) and of fusion of the prostasome to spermatozoa on progesterone-induced [Ca2+]i increase. No effect at all was noticed in the absence of progesterone stimulation. In the presence of the hormone, both CysNO and fusion increased the progesterone effect. This phenomenon was much more evident if the two treatments were used together. We conclude that both NO and fusion with prostasomes act on the progesterone-dependent pathway additively. Probably the effects are independent.
authors.affiliation: Laboratorio di Biochimica, Dipartimento di Medicina Interna e Scienze Endocrine e Metaboliche, University of Perugia, Via del Giochetto, 06122 Perugia, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Arienti
authors.forename: Enrico
authors.initials: E
authors.lastname: Carlini
authors.forename: Carla
authors.initials: C
authors.lastname: Saccardi
authors.forename: Carlo Alberto
authors.initials: CA
authors.lastname: Palmerini
mesh_terms: D002118:Calcium / Q000378:metabolism*; D003545:Cysteine / Q000031:analogs & derivatives* / Q000494:pharmacology; D022162:Cytoplasmic Vesicles / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008561:Membrane Fusion; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D011374:Progesterone / Q000494:pharmacology*; D026403:S-Nitrosothiols / Q000494:pharmacology; D013094:Spermatozoa / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D020030:Nitric Oxide Donors; D026403:S-Nitrosothiols; D009569:Nitric Oxide; D011374:Progesterone; C021315:S-nitrosocysteine; D003545:Cysteine; D002118:Calcium