Distribution, morphology and epithelial interactions of bovine spermatozoa in the oviduct before and after ovulation: A scanning electron microscope study

Hunter, Richard; Fléchon, B.; Fléchon, J.‐E.

doi:10.1016/0040-8166(91)90020-t

Cited by 152 publications

(118 citation statements)

References 34 publications

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“…However, both agonists completely blocked cap modifications in another subpopulation of sperm that could respond between 2-6 hr, suggesting that AEA-signaling via cannabinoid receptors modulates this process. Altered acrosomal caps have been observed by other investigators in human, rodent, and bovine sperm in vitro, and/or in vivo within the isthmus, ampulla, and cumulus (Yanagimachi and Phillips, 1984;Lee et al, 1987a,b;Hunter et al, 1991;Kligman et al, 1991;Nolan et al, 1992;Kim et al, 2001a,b). Acrosomal cap modifications may be morphological correlates of capacitation.…”

Section: Discussionmentioning

confidence: 84%

Evidence that anandamide‐signaling regulates human sperm functions required for fertilization

Schuel

Burkman

Lippes

et al. 2002

Molecular Reproduction Devel

129

123

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Ejaculated mammalian sperm require several hours exposure to secretions in female reproductive tracts, or incubation in appropriate culture medium in vitro, before acquiring the capacity to fertilize eggs. Arachidonylethanolamide (AEA), also known as anandamide, is a novel lipid-signal molecule that is an endogenous agonist (endocannabinoid) for cannabinoid receptors. We now report that AEA is present in human seminal plasma, mid-cycle oviductal fluid, and follicular fluid analyzed by high-performance liquid chromatography/mass spectrometry. Sperm are sequentially exposed to these reproductive fluids as they move from the vagina to the site of fertilization in the oviduct. Specific binding of the potent cannabinoid agonist [3 H]CP-55,940 to human sperm was saturable (K D 9.71 AE 1.04 nM), suggesting that they express cannabinoid receptors. R-methanandamide , a potent and metabolically stable AEA analog, and (À)D 9 tetrahydrocannabinol (THC), the major psychoactive constituent of Cannabis, modulated capacitation and fertilizing potential of human sperm in vitro. AM-356 elicited biphasic effects on the incidence of hyperactivated sperm motility (HA) between 1 and 6 hr of incubation: at (2.5 nM) it inhibited HA, while at (0.25 nM) it stimulated HA. Both AM-356 and THC inhibited morphological alterations over acrosomal caps between 2 and 6 hr (IC 50 5.9 AE 0.6 pM and 3.5 AE 1.5 nM, respectively). Sperm fertilizing capacity, measured in the Hemizona Assay, was reduced 50% by (1 nM) AM-356. These findings suggest that AEA-signaling may regulate sperm functions required for fertilization in human reproductive tracts, and imply that smoking of marijuana could impact these processes. This study has potential medical and public policy ramifications because of the incidence of marijuana abuse by adults in our society, previously documented reproductive effects of marijuana, and the ongoing debate about medicinal use of marijuana and cannabinoids.

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Section: Discussionmentioning

confidence: 84%

Evidence that anandamide‐signaling regulates human sperm functions required for fertilization

Schuel

Burkman

Lippes

et al. 2002

Molecular Reproduction Devel

129

123

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“…Scanning electron microscopic studies undertaken jointly with M. and Mme Fléchon further emphasised the pre-ovulatory storage of viable spermatozoa in the caudal isthmus and the intimate arrangement of the head with the duct epithelium [11][12][13]. This orientation of the head had been noted during prolonged sperm storage in bats [14], and soon was to become termed sperm binding on account of the adhesive reaction.…”

Section: Functional Sperm Reservoirmentioning

confidence: 99%

The Fallopian tubes in domestic mammals: how vital is their physiological activity?

Hunter¹

2005

Reprod. Nutr. Dev.

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-Set in an historical perspective, this essay examines diverse physiological aspects of Fallopian tube function in domestic animals and man. Microsurgical experiments are described that established the role of the isthmus in imposing a sperm gradient up to the site of fertilisation. Resection of the isthmus followed by reanastomosis of the remaining portions of the tube generated a high incidence of polyspermy in mated animals. Scanning electron microscopy and surgical studies revealed that spermatozoa were arrested and stored in the caudal portion of the isthmus before ovulation, the so-called functional sperm reservoir. There were specific adhesion contacts between the sperm head and endosalpingeal microvilli or cilia. Further experiments indicated that very large numbers of competent spermatozoa could be released from pre-ovulatory binding by microinjections of a solution of progesterone in oil under the serosal layer of the tube: when suitably timed, such treatment led to a high incidence of polyspermic fertilisation. Avid sperm binding in the caudal isthmus before ovulation prevents myosalpingeal activity leading to abnormal fertilisation, as might occur with multiple mating. Temperatures in the reproductive system were assessed and the caudal isthmus was found to be cooler than the ampulla during the pre-ovulatory phase of sperm storage. Finally, the existence of fluid microenvironments within the Fallopian tubes was reported, and the role of suspended cumulus-corona cells in amplifying signals from the zygote examined. An impact of Fallopian tube fluids on embryonic gene expression was also considered -an influence that may be further imposed if such fluids have access to the uterine lumen. tubal anastomosis / isthmus / sperm gradient / fertilisation / polyspermy / microenvironments / temperature

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“…The term functional sperm reservoir was therefore proposed for the caudal isthmus since it represents the region from which fertilising spermatozoa are released close to the time of ovulation (Hunter et al, 1980;Hunter, 1981). Scanning electron microscopy of oviduct tissues removed at surgery and subjected to gentle rinsing before fixation suggested some form of adhesion between the sperm head and protruding epithelial organelles of the caudal isthmus, either cilia or microvilli or both (Fléchon and Hunter, 1981;Hunter et al, 1987Hunter et al, , 1991, a conclusion also reached by Yanagimachi (1990, 1991), Pollard et al (1991), Suarez et al (1991) and Mburu et al (1997). Such an intimate form of contact between male gametes and this region of the female genital tract is now known to involve chemical bonding (DeMott et al, 1995).…”

Section: Functional Sperm Reservoirmentioning

confidence: 99%

“…Although molecular details are not yet available for sequential modifications to the plasma membrane, progression of motile spermatozoa within the uterus and through the utero-tubal junction seemingly facilitates binding interactions with the epithelium of the caudal isthmus (see Hunter et al, 1987Hunter et al, , 1991. In support of this point, surgical instillation of aliquots of freshly ejaculated spermatozoa directly into the caudal isthmus of pigs shortly before ovulation results in little or no binding and rapid passage of large numbers of spermatozoa to the site of fertilisation and a high incidence of polyspermy (Hunter, 1973(Hunter, , 1976.…”

Section: In Vitro Models Of Sperm Bindingmentioning

confidence: 99%

Sperm release from oviduct epithelial binding is controlled hormonally by peri‐ovulatory graafian follicles

Hunter

2007

Molecular Reproduction Devel

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To avoid inappropriate conclusions being drawn from the extensive use of in vitro preparations of sperm-oviduct epithelial binding, it is recalled that events in the genital tract of mammals are regulated by the gonads, primarily by their changing secretion of steroid hormones. Key observations from in vivo models are used to emphasise the dynamic interactions between viable sperm cells and the caudal (distal) portion of the oviduct isthmus, the site of the functional sperm reservoir. These include (1) preovulatory arrest and epithelial binding of intact sperm cells and thereby suppression of completion of capacitation, (2) peri-ovulatory activation and release from binding of discrete sub-populations of competent spermatozoa, and (3) post-ovulatory liberation of large numbers of spermatozoa. These observations underline the influence of endocrine regulation of sperm binding and release by peri-ovulatory Graafian follicles, a point brought out by the enhanced sperm release prompted by diverse treatments with solutions of progesterone. In the light of this evidence, the suitability of in vitro preparations for clarifying physiological events should be questioned, especially if myosalpingeal catecholamines diffusing out of the autonomic nervous system contribute to sperm activation and/or release. None of this is to infer that sperm cells themselves are without influence on their epithelial binding reaction(s). Nor is it to suggest that in vitro models of sperm-oviduct binding are without relevance to the development of sperm evaluation technologies. However, pre-ovulatory sperm-epithelial binding and a regulated peri-ovulatory release should be seen as vital tactics in the overall strategy of achieving successful monospermic fertilisation. Mol. Reprod. Dev. 75: 167-174, 2008.

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Distribution, morphology and epithelial interactions of bovine spermatozoa in the oviduct before and after ovulation: A scanning electron microscope study

Cited by 152 publications

References 34 publications

Evidence that anandamide‐signaling regulates human sperm functions required for fertilization

Evidence that anandamide‐signaling regulates human sperm functions required for fertilization

The Fallopian tubes in domestic mammals: how vital is their physiological activity?

Sperm release from oviduct epithelial binding is controlled hormonally by peri‐ovulatory graafian follicles

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