Type-1 Cannabinoid Receptors Reduce Membrane Fluidity of Capacitated Boar Sperm by Impairing Their Activation by Bicarbonate

Background Mammalian spermatozoa acquire their full fertilizing ability (so called capacitation) within the female genital tract, where they are progressively exposed to inverse gradients of inhibiting and stimulating molecules. Methodology/Principal Findings In the present research, the effect on this process of anandamide, an endocannabinoid that can either activate or inhibit cannabinoid receptors depending on its concentration, and bicarbonate, an oviductal activatory molecule, was assessed, in order to study the role exerted by the type 1 cannabinoid receptor (CB1R) in the process of lipid membrane remodeling crucial to complete capacitation. To this aim, boar sperm were incubated in vitro under capacitating conditions (stimulated by bicarbonate) in the presence or in the absence of methanandamide (Met-AEA), a non-hydrolysable analogue of anandamide. The CB1R involvement was studied by using the specific inhibitor (SR141716) or mimicking its activation by adding a permeable cAMP analogue (8Br-cAMP). By an immunocytochemistry approach it was shown that the Met-AEA inhibits the bicarbonate-dependent translocation of CB1R from the post-equatorial to equatorial region of sperm head. In addition it was found that Met-AEA is able to prevent the bicarbonate-induced increase in membrane disorder and the cholesterol extraction, both preliminary to capacitation, acting through a CB1R-cAMP mediated pathway, as indicated by MC540 and filipin staining, EPR spectroscopy and biochemical analysis on whole membranes (CB1R activity) and on membrane enriched fraction (C/P content and anisotropy). Conclusions/Significance Altogether, these data demonstrate that the endocannabinoid system strongly inhibits the process of sperm capacitation, acting as membrane stabilizing agent, thus increasing the basic knowledge on capacitation-related signaling and potentially opening new perspectives in diagnostics and therapeutics of male infertility

Rapport VI. 4. Le naviplane, aéroglisseur marin à coussins multiples

The ‘Naviplane* is the sea equivalent of Société Bertin’s land version of an air-cushion craft, the ‘ Terraplane ’. It can reach speeds of up to about 150 k.p.h. with satisfactory stability and comfort over rough water. Methods of determining the performance and stability of this type of craft are described. Though still more or less in their infancy, results obtained and confirmed experimentally so far are quite interesting.Sur le principe de l’Aéroglisseur «Terraplane », créé par la société Bertin, a été conçu un appareil marin à coussins d’air, le Naviplane, qui permettra d’atteindre de très grandes vitesses sur l’eau, de l’ordre de 150 km/h, tout en assurant une excellente stabilité et un bon confort sur mer agitée. Les méthodes de détermination des performances et de la stabilité, applicables à ce type d’engin, sont présentées ici. Bien que ces méthodes soient encore en cours de mise au point, elles ont déjà fourni des résultats intéressants qui sont confirmés par plusieurs expériences.Guienne P. Rapport VI. 4. Le naviplane, aéroglisseur marin à coussins multiples. In: Le rôle de la mécanique des fluides dans les progrès récents des techniques. 1967

Tests de fertilité chez l'animal domestique par fécondation in vitro

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Onset of the first S-phase is determined by a paternal effect during the G1-phase in bovine zygotes

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Evaluation of bull semen fertility by homologous in vitro fertilization tests

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