Ovum Transport Research Articles

The effect of ovarian follicular fluid and peritoneal fluid on Fallopian tube ciliary beat frequency

The Fallopian tube undergoes well-recognized changes during the ovarian cycle. Ciliary beat frequency (CBF) increases during the secretory phase of the cycle. The stimulus is unknown, although CBF is known to be hormone responsive. At ovulation, follicular fluid is released into the peritoneal cavity and enters the Fallopian tube. We hypothesized that this fluid may provide the stimulus for the increase in CBF detected after ovulation. Using a technique which records changes in light intensity, we have studied the effect of pre-ovulatory follicular fluid on CBF of Fallopian tube epithelial cells, and compared this with the effect of either peritoneal fluid or culture medium alone. Follicular fluid samples from 13 women undergoing IVF were collected by selective aspiration of individual follicles. Peritoneal fluid was collected from six women undergoing laparoscopic sterilization. Fallopian tubes were collected from 10 women who underwent hysterectomy for benign conditions. After 24 h incubation, there was a highly significant difference in CBF between the Fallopian tube samples bathed in follicular fluid (mean CBF +/- SEM: 6.34 +/- 0.02 Hz) compared with explants bathed in either medium (4.20 +/- 0.06 Hz) or peritoneal fluid (5.24 +/- 0.03 Hz) (P < 0.005). There was also a significant difference in CBF between tissues bathed in secretory (5.47 +/- 0.03 Hz) compared with proliferative phase peritoneal fluid (4.75 +/- 0.02 Hz) (P < 0.005). The increase in CBF detected after ovulation may aid ovum pick-up and transport along the Fallopian tube. Factor(s) within human follicular fluid and secretory phase peritoneal fluid may be responsible for this increase in CBF.

146 EFFECT OF MATERNAL AGE AND PARITY ON THE PRESENCE AND DISTRIBUTION OF CADHERIN-E IN HAMSTER EMBRYOS DURING PRE-IMPLANTATION DEVELOPMENT AND TRANSPORT

Our knowledge of the factors that contribute to in vivo embryo development and transport are still incomplete. Although there is solid evidence that the hormonal state of the female regulates ovum transport in mammals, recently, because of significant differences between the rate of oviduct transport of fertilized and unfertilized eggs in several mammalian species, there have been some reports showing that the conceptus itself may auto regulates its own transport. During the initial phases of embryonic development the distribution of E-cadherin, a calcium dependent cell adhesion molecule, changes from a general distribution over the whole surface of the blastomeres to become almost exclusively localized over the points of contact between blastomeres. This change on E-cadherin localization has been related to the beginning of embryo compactation and is considered as the initial stage of differentiation. We have recently shown that pre-implantation embryo development and transport is highly synchronous in nuliparous young females (NYF), but not in adults. Nuliparous adult (8 months) females (NAF) and multiparous adult females (MAF) show significant asynchrony and retard on early embryo development. In NYF, all 8 cells embryos reached the uterus by 62 h after coitus. In adult females, both nuliparous and multiparous, a considerable number of 8 cells embryos fail to migrate into the uterus even at 67 h after coitus. E-cadherin distribution was studied by indirect immunofluorescence and confocal microscopy during preimplantation embryo development in three groups, NYF, MAF, and NAF, of regularly cycling golden hamster (Mesocricetus auratus) females. Females were mated with males of proven fertility. Only 15 minutes were allowing for mating. Time of ejaculation was registered. Females were sacrificed from 60 to 69 h after coitus. Corpora lutea were counted in both ovarian surfaces. Oviducts and uterine horns were flushed separately and embryo number, stage of development, and distribution were recorded. Cell numbers, cadherin distribution and the number of cadherin-dependent cell to cell contacts were established in at least 20 embryos per group and at each of the different hours of the study. Presence and distribution of E-cadherin on 4-, 6-, and 8-cell blastomeres embryos differs accordingly with the parity and age of the females. Differences are particularly important at the eight-cell stage 80 to 93% of the embryos from NYF showed normal cadherin dependent cell contacts with all neighboring cells. In the case of multiparous adult females (MAF) only 52 to 68% of the embryos showed normal cell to cell contacts. These results will be discussed in relation to the respective role that the female hamster and the conceptus itself play in early embryo development and transport. Our results also indicate that in spite of the significantly higher ovulation rate of old females, their reproductive efficiency were significantly lower than that of NYF.

Oviduct contractile response to vaginal distension: identification of vagino-tubal reflex

The effect of vaginal distension on the oviduct contractile activity during penile thrusting at coitus could not be traced in the literature. We investigated the hypothesis that vaginal distension effects oviduct contraction, which assists in ovum transport along the oviduct. Oviduct pressure was measured upon vaginal condom distension in 16 women (mean age 32.2+/-1.2 years) scheduled for abdominal hernia repair and oviduct ligation for sterilization. The test was repeated after individual anesthetization of the vagina and oviduct. Ten milliliters vaginal distension effected pressure elevation of the ampullary (AO) and isthmic (IO) parts of the oviduct (p<0.01, p<0.01 respectively) and a decrease in intramural oviduct (IMO; p<0.01). Twenty milliliters distension further increased the pressure in the AO and the IO (p<0.001, p<0.001) and decreased it in IMO (p<0.001). Vaginal distension with greater volumes produced an oviduct pressure response similar to that with 20 ml distension (p>0.05). Vaginal distension of anesthetized vagina or oviduct did not evoke the oviduct pressure response, but saline infusion did. Vaginal distension seems to produce oviduct motile activity as evidenced by oviduct pressure changes, which appear to assist in sperm-ovum transport and fertilization. These oviduct changes are suggested to occur reflexly through the "vagino-tubal reflex." Pathologic changes of the oviduct presumably interfere with this reflex action, a point that needs to be investigated.

412 Identification of pesticides sex-specific gonadal toxicity

While there are certain differences between biological responses to C-21 progestogens and the 19-norsteroids, precoital progestogens in general interfere with sperm transport, fertilization, and ovum transport. A 36 hour interval was required to achieve 100 per cent precoital contraceptive effectiveness in the rabbit. At marginal doses or timing, blastocyst degeneration may occur, and with large doses of progesterone at the time of coitus some teratogenic effects were noted. Postcoital estrogen is associated with lowering of plasma progesterone levels. Concomitant progesterone administartion, however, does not completely reverse the interceptive effect of estrogen. Direct effects on the endometrium include disintegration of the nucleolar channel system, retention of glycogen in endometrial glands, decreased alkaline phosphatase, and lowered endometrial carbonic anhydrase. The latter may be the basic mechanism of action.

Estrogen receptor, cyclic adenosine monophosphate, and protein kinase A are involved in the nongenomic pathway by which estradiol accelerates oviductal oocyte transport in cyclic rats.

This investigation examined the role of estrogen receptor (ER) on the stimulatory effect of estradiol (E2) on protein phosphorylation in the oviduct as well as on E2-induced acceleration of oviductal oocyte transport in cyclic rats. Estrous rats were injected with E2 s.c. and with the ER antagonist ICI 182 780 intrabursally (i.b.), and 6 h later, oviducts were excised and protein phosphorylation was determined by Western blot analysis. ICI 182 780 inhibited the E2-induced phosphorylation of some oviductal proteins. Other estrous rats were treated with E2 s.c. and ICI 182 780 i.b. The number of eggs in the oviduct, assessed 24 h later, showed that ICI 182 780 blocked the E2-induced egg transport acceleration. The possible involvement of adenylyl cyclase, protein kinase A (PK-A), protein kinase C (PK-C), or tyrosine kinases on egg transport acceleration induced by E2 was then examined. Selective inhibitors of adenylyl cyclase or PK-A inhibited the E2-induced egg transport acceleration, whereas PK-C or tyrosine kinase inhibitors had no effect. Furthermore, forskolin, an adenylyl cyclase activator, mimicked the effect of E2 on ovum transport and E2 increased the level of cAMP in the oviduct of cycling rats. Finally, we measured PK-A activity in vitro in the presence of E2 or E2-ER complex. Activity of PK-A in the presence of E2 or E2-ER was similar to PK-A alone, showing that E2 or E2-ER did not directly activate PK-A. We conclude that the nongenomic pathway by which E2 accelerates oviductal egg transport in the rat requires absolute participation of ER and cAMP and partial participation of PK-A signaling pathways in the oviduct.

Postovulatory effect of intravenous administration of lipopolysaccharide (E. coli, O55:B5) on the contractile activity of the oviduct, ova transport, binding of accessory spermatozoa to the zona pellucida and embryo development in sows.

The effect of lipopolysaccharide (LPS) (E. coli, O55:B5), administered 18 h after ovulation in the second oestrus after weaning, on the contractile activity of the oviduct, ova transport, sperm binding to zona pellucida (ZP) and embryo development, was studied in 14 Swedish crossbred (Landrace Yorkshire) multiparous sows. The endotoxin group (E-group) sows were administered with 300 ng/kg of LPS while the control group (C-group) sows were administered with 5 ml of saline i.v. via an indwelling jugular cannula. Immediately after evidence of standing oestrus, a Millar pressure transducer was placed intraluminally about 3 cm into the mid-isthmus, via laparotomy. Pressure recordings of the oviduct were collected from all conscious sows until slaughter. After slaughter, the genital tract opposite to the side with the transducer was retrieved, and three equal isthmic segments and the first third of the uterine horn part adjacent to the utero-tubal-junction (UTJ) were flushed separately to recover the ova. The intervals (mean+/-SD) from ovulation to slaughter (OS) and insemination to ovulation (IO) were not different between the E-group (44.5 +/- 5.7 h; 13.3 +/- 6.5 h) and the C-group (42.7 +/- 5.9 h; 14.8 +/- 4.1 h), respectively. Ova recovery rate (RR) in the E-group (80.2 +/- 22.9%) did not differ from that in the C-group (85.2 +/- 4.5%). The frequency distribution of ova recovered in the different segments did not significantly (p > 0.05) differ between the groups. The E-group showed higher cleavage rate than controls. A higher proportion of spermatozoa bound to the ZP was also found in the E-group compared with controls. The isthmic intraluminal pressure slightly increased (p = 0.07) 18 h after ovulation and immediately following LPS in the E-group, compared with the C-group. The frequencies of phasic pressure fluctuations were significantly (p < 0.05) lower at 30 and 38 h after ovulation in the E- than in the C-group. It can be concluded from the present study that a single i.v. administration of LPS (300 ng/kg body weight) to sows, 18 h after ovulation might be associated with changes in isthmic pressure and the frequency of phasic pressure fluctuations, increased numbers of spermatozoa attached to the ZP and an enhanced embryo development but not with ova transport rates.

Postovulatory effect of repeated administration of prostaglandin F 2α on the endocrine status, ova transport, binding of accessory spermatozoa to the zona pellucida and embryo development of recently ovulated sows

We investigated the postovulatory effect of repeated administration of prostaglandin F 2α (PGF 2α) on the endocrine status, ova transport, binding of accessory spermatozoa to the zona pellucida (ZP) and embryo development of recently ovulated sows. We used altogether 10 Swedish crossbred (Landrace×Yorkshire) multiparous sows. The treatment group (P-group) was administered 1 mg of PGF 2α intravenously every 6 h via an indwelling jugular cannula, commencing 4–8 h after ovulation was detected in the second estrus after weaning. All sows were inseminated once and blood was sampled until the end of the experimental period. After slaughter, we immediately recovered the reproductive tracts and divided them into three equal isthmic segments (IST1, IST2 and IST3) and a third of the uterine horn from the utero-tubal-junction (UTJ), and we flushed each one with PBS for ova recovery. We immediately stained the ova and examined them under epi-fluorescence illumination. We found the highest proportion of ova in the P-group in IST1 (41.5%), while we found the highest proportion in the C-group in the uterus (40.7%). A total of 68.7% of ova in the P-group had more than 50 accessory spermatozoa attached to the ZP, compared with 36.7% in the C-group sows. A total of 77% of ova had more than three blastomeres in the P-group, compared with 73% in the C-group. PGF 2α metabolite and cortisol levels were elevated ( P<0.05) following every PGF 2α administration. Despite peaks, we saw no changes ( P>0.05) in progesterone levels between the P-group and the C-group. We saw no differences ( P>0.05) in estradiol-17β levels between the P-group and the C-group. We concluded that PGF 2α stimulates the hypothalamus–pituitary–adrenal axis, as evidenced by the elevation of cortisol and progesterone but not estradiol-17β. Furthermore, repeated PGF 2α administration might be associated with a delayed ova transport and an increased number of accessory spermatozoa bound to the ZP. However, the effect of PGF 2α on embryo development is unclear.

Immunohistochemical characterization of efferent neurons innervating the oviduct in the pig located in the sympathetic chain ganglia

The present study was aimed at disclosing the pattern(s) of putative co-incidence of tyrosine hydroxylase (TH), dopamine -hydroxylase (DH), neuropeptide Y (NPY), substance P (SP), calcitonin gene-related peptide (CGRP) and nitric oxide synthase (NOS) within the porcine &amp;ldquo;oviductal&amp;rdquo; efferent neurons using combined retrograde tracing and double-labelling immunohistochemistry. The fluorescent retrograde tracer Fast Blue (FB) was injected into the wall of the ampullar (n = 5) and isthmal (n = 5) part of the organ in ten sexually immature female pigs. After a survival period of three weeks sympathetic chain ganglia (SCG) were collected. 10 &amp;micro;m-thick cryostat sections of the ganglia were examined for the presence of FB-positive (FB&lt;sup&gt;+&lt;/sup&gt;) nerve cells under the fluorescent microscope. Tracered neurons were processed for double-labelling immunofluorescence according to the method of Wessendorf and Elde. Retrograde labelling revealed a population of &amp;ldquo;oviductal&amp;rdquo; efferent neurons located in the thoracic (T) and lumbar (L) SCG at the level of T&lt;sub&gt;14&lt;/sub&gt; to L&lt;sub&gt;5&lt;/sub&gt;. Double-labelling immunofluorescence allowed several subpopulations of the studied perikarya to be distinguished. The largest one consisted of TH&lt;sup&gt;+&lt;/sup&gt;/DH&lt;sup&gt;+&lt;/sup&gt; (immunopositive) nerve cells. The moderate number of FB&lt;sup&gt;+&lt;/sup&gt; nerve cells expressed TH/NPY- immunoreactivity (IR). The tracered neurons did not show SP, CGRP and NOS immunoreactivity. Because identically coded nerve fibres have been observed within the wall of the porcine oviduct it can be assumed that TH&lt;sup&gt;+&lt;/sup&gt;/DH&lt;sup&gt;+&lt;/sup&gt; or TH&lt;sup&gt;+&lt;/sup&gt;/NPY&lt;sup&gt;+&lt;/sup&gt; neurons are involved in the control the oviductal tonus and ovum transport.

Fallopian tube ciliary beat frequency in relation to the stage of menstrual cycle and anatomical site.

The cyclical changes in ciliary structure and motion within the human Fallopian tube are well documented. Previous investigators have studied ciliary beat frequency (CBF) in relation to menstrual cycle and anatomical site, but with conflicting results. Using a technique that records variations in light intensity, we have studied the changes in CBF in relation to the menstrual cycle and anatomical site. Fallopian tubes were collected from 26 women who underwent hysterectomy for benign conditions. Menstrual history, hormone profile and endometrial biopsy results were used to determine the stage of the cycle. Fourteen women were in the proliferative phase, and 12 women in the secretory phase. Mean CBF for all subjects was 5.3 plus minus 0.2 Hz. There was no significant difference in CBF in relation to anatomical site. In the fimbrial region the ciliary beat was faster in the secretory (5.8 plus minus 0.3 Hz) as compared with the proliferative phase (4.9 plus minus 0.2 Hz), P < 0.02. It is possible that this increase in fimbrial CBF may contribute to ovum retrieval and transport after ovulation. However, the reproductive significance of the changes in CBF in relation to the menstrual cycle needs further investigation.

Impact of Postovulatory Food Deprivation on the Ova Transport, Hormonal Profiles and Metabolic Changes in Sows

The effect of food deprivation on ova transport, hormonal profiles and metabolic changes was studied in 20 crossbred multiparous sows during their second oestrus after weaning. To determine the time of ovulation, transrectal ultrasonographic examination was performed. The sows were divided into 2 groups, one control group (C-group), which was fed according to Swedish standards, and one experimental group (E-group). The E-group sows were deprived of food from the first morning meal after ovulation until slaughter. Blood samples were collected every second hour from about 12 h before expected ovulation in the second oestrus after weaning until slaughter and were analysed for progesterone, prostaglandin F2α-metabolite, insulin, glucose, free fatty acids and triglycerides. All sows were slaughtered approximately 48 h after ovulation and the genital tract was recovered. The isthmic part of the oviduct was divided into 3 equally long segments and flushed separately with phosphate buffered saline (PBS). Uterine horns were also flushed with PBS. A significantly greater number of ova were found in the first and second part of the isthmus in the E-group (p = 0.05) while in the C-group most of the ova were found in the third part of the isthmus or the uterus (p = 0.01). The level of prostaglandin F2α-metabolite was significantly higher in the E-group compared with the C-group. The concentration of progesterone increased in both groups after ovulation but there were no significant differences between the groups. The other blood parameters showed that the food-deprived sows were in a catabolic state. The 48 h period of fasting results, directly or indirectly in an delayed ova transport, which may be due to a delayed relaxation in the smooth circular muscle layer of the isthmus.

Postovulatory effect of repeated intravenous administration of ACTH on the contractile activity of the oviduct, ova transport and endocrine status of recently ovulated and unrestrained sows

The effect of repeated intravenous administration of ACTH (Synacthen® depot) on the contractile activity of the oviduct, ova transport and endocrine status was studied in 11 Swedish crossbred (Landrace × Yorkshire) multiparous sows. In the second estrus after weaning, the ACTH group (Group A, n=6) sows were administered 0.01 mg/kg body weight of ACTH every 6 h commencing 4 to 8 h after ovulation, whereas the control group (Group C, n=5) sows were administered saline solution. Immediately after standing estrus, a Millar® pressure transducer was placed about 3 cm into the isthmus via a laparotomy. Blood samples for hormonal analyses and pressure recordings of the oviduct were collected from all sows until slaughter. After slaughter, the genital tract opposite to the side with the transducer was retrieved, and 3 equal isthmic segments and the first third of the uterine horn portion adjacent to the UTJ were flushed separately for ova recovery. Cortisol levels were significantly (P<0.05) elevated after ACTH administration. Progesterone and PGF 2α metabolite levels were significantly (P<0.05) elevated only after the first ACTH administration. No significant differences (P>0.05) were seen in the mean pressure and frequencies of phasic pressure fluctuations either before or after every ACTH administration between Groups A and C. No significant difference (P>0.05) was seen in the proportion of ova recovered in the different segments between Groups A and C. It can be concluded from the present study that the administration of ACTH (0.01 mg/kg body weight) to sows at 4 to 8 h after ovulation, and after each subsequent ACTH administration, elevates cortisol levels, whereas progesterone and PGF 2α metabolite levels are elevated only after the first treatment, and that this has no effect on the mean isthmic pressure, the frequency of phasic pressure fluctuations or ova transport.

Infections and infertility

Infertility affects 10–15% of all couples. Pelvic infections are an important cause of infertility, primarily as a result of tubal damage. Damage to the fallopian tubes from infections may be due to adhesions, tubal mucosal damage, or tubal occlusion that interferes with normal ovum transport. The infections most commonly related to infertility include gonorrhea, chlamydia, and pelvic inflammatory disease. Tuberculosis also is a common cause of infertility in Third World nations. Sequelae resulting from these infections include ectopic pregnancy, infertility, chronic pelvic pain, hydrosalpinx, and tuboovarian abscess. Neisseria gonorrhoeae and Chlamydia trachomatis are the primary causes of pelvic inflammatory disease. Chlamydial infections may be asymptomatic, and the resulting salpingitis is often referred to as silent pelvic inflammatory disease. Polymicrobial infection with other organisms such as anaerobes or facultative aerobes may be initiated by gonorrhea, chlamydia, or both. Early recognition of infection, prompt institution of appropriate antibiotic therapy, and proper follow-up are important to prevent the sequelae of pelvic inflammatory disease. Surgical intervention may be needed to treat immediate or long-term sequelae of infection. Prevention of pelvic infections should be a high priority. Fortunately, treatment options such as tubal microsurgery and assisted reproductive technologies offer couples reproductive options even when infertility occurs as the result of a previous pelvic infection.

Effect of Stressors on Ova Transport in the Pig

Effect of Stressors on Ova Transport in the Pig

Effect of Stressors on Ova Transport in the Pig

Effect of Stressors on Ova Transport in the Pig

Effects of post-ovulatory food deprivation on the hormonal profiles, activity of the oviduct and ova transport in sows.

The objective of the present study was to investigate the effect of post-ovulatory food deprivation on the hormonal profiles and consequently on the activity of the oviduct and ova transport in sows. Sows were randomly allocated to the control (C-group, n=6) or fasted (F-group, n=5) group. The F-group sows were fasted for four meals starting with the morning meal after detection of ovulation in the second oestrus after weaning. Ovulation was checked by transrectal ultrasonography. Blood was collected for the analyses of progesterone, oestradiol-17beta, prostaglandin F(2 approximately ) metabolite, insulin, free fatty acids and triglycerides. Oviductal isthmic motility was monitored on Polyview before and after ovulation until the time of slaughter. After slaughter, the isthmus opposite the side with transducer was divided into three equal segments and flushed separately and a third of the uterine horn part from the utero-tubal-junction (UTJ) was also flushed. A high proportion of ova in the F-group was found in the first and second parts of the isthmus. In the C-group, a high proportion of ova was found in the third part of the isthmus and the uterus. The mean isthmic pressure in the C-group decreased significantly (P<0.05) during the period immediately after ovulation while in the F-group mean pressure remained unchanged. The frequency of phasic pressure fluctuations were significantly (P<0.05) higher in the F- than in the C-group 13 to 24 h after ovulation. No significant differences in progesterone concentrations were seen between the two groups of sows. Prostaglandin metabolite levels were significantly (P<0.05) higher in the F-group than in the C-group. Oestradiol-17beta levels significantly (p<0.05) decreased earlier in the F- than in the C-group. Serum insulin levels were significantly (p=0.05) lower in the F- than in the C-group while free fatty acids were significantly (p<0.01) higher in the F- than in the C-group. There were no significant differences in the serum levels of triglycerides between the F- and the C-group. Therefore, it can be concluded in the present study that food deprivation is associated with changes in the hormonal profiles, activity of the oviduct and a delay of ova transport in sows.

The influence of inhibited prostaglandin biosynthesis on post-ovulatory oviductal ova transport in sows

Changes in prostaglandin and progesterone concentrations after ovulation seem to affect reproductive functions in the sow. The influence of lowered prostaglandin levels on ova transport velocity through the isthmus part of the oviduct, and on progesterone concentrations, was studied during the second estrus after weaning in thirteen purebred Yorkshire multiparous sows. To determine the time of ovulation transrectal ultrasonographic examination was performed. In the second estrus, six sows were given intravenous injections of flunixin meglumine (2.2 mg/kg body weight) every sixth hour from 4 to 8 h after time of ovulation until about 48 h after ovulation, at which time the sows were slaughtered. Blood samples were collected every second hour from about 12 h before ovulation until slaughter. Progesterone and prostaglandin F 2α (PGF 2α) metabolite levels were determined. Immediately after slaughter the isthmus part of the oviducts were cut into 3 equally long segments and the number of ova in each segment, and in the upper part of the uterine horns, was determined. Before start of treatment, PGF 2α metabolite levels were similar in the 2 groups (P = 0.84). In the treatment group, PGF 2α values dropped to below the detection limit immediately after start of treatment, whereas in the control group the concentrations were quite stable throughout the sampling period (P = 0.005). Ova recovery rate was 94 % in the treatment group and 95 % in the control group. At time of slaughter, in the treatment group ova had on average passed 2.1 segments whereas in the control group the ova had passed 2.5 segments (P = 0.57). The progesterone levels increased continuously in both groups after ovulation but there was no difference in the mean progesterone concentrations between the two groups before (P = 0.96) or after (P = 0.58) ovulation. It can be concluded that the transport of ova through the isthmus part of the oviduct is unaffected by an inhibition of prostaglandin synthesis immediately after ovulation. Furthermore, the post-ovulatory progesterone profile seems unaffected by lowered PGF 2α levels.

Effect of nitric oxide synthase inhibitors on ovum transport and oviductal smooth muscle activity in the rat oviduct.

The effect of the inhibition of nitric oxide synthase (NOS) on ovum transport and oviductal motility in rats was investigated. Three different NOS inhibitors were injected into the ovarian bursa at oestrus or day 3 of pregnancy. Oviducts and uteri were flushed 24 h later and the presence of ova was recorded. In oestrous and pregnant rats, treatment resulted in accelerated egg transport, as shown by a decrease in the number of ova present in the oviducts. In cyclic rats, intrabursal injection of 1 mg kg-1 of either N-monomethyl-L-arginine (L-NMMA) or N omega nitro-L-arginine methyl ester (L-NAME) elicited a 30% reduction in the number of ova present in the oviducts, whereas in pregnant animals, the same dose of L-NMMA produced a reduction of 40%. Simultaneous administration of the NO donor spermine NONOate (5 mg kg-1) completely reversed the effect of L-NMMA. Tubal motility was assessed by microsphere displacement analysis within the oviduct. Surrogate ova were transferred to the oviductal lumen at oestrus and 24 h later the effect of intraoviductal injection of 1 microgram L-NMMA or vehicle was assessed. The microspheres in the isthmus showed an oscillating motion, and periods in which movement was not detectable. However, L-NMMA treatment produced a 3.6-fold increase in the maximum instant velocities and a significant reduction in the resting periods of the microspheres compared with the control group (P < 0.001). These results provide evidence that NO inhibition increases tubal motility that results in accelerated ovum transport, and indicate that NO could act as a paracrine signal between different layers of the oviductal wall, providing a role for endogenous NO in regulation of tubal function.

Effect of nitric oxide synthase inhibitors on ovum transport and oviductal smooth muscle activity in the rat oviduct

The effect of the inhibition of nitric oxide synthase (NOS) on ovum transport and oviductal motility in rats was investigated. Three different NOS inhibitors were injected into the ovarian bursa at oestrus or day 3 of pregnancy. Oviducts and uteri were flushed 24 h later and the presence of ova was recorded. In oestrous and pregnant rats, treatment resulted in accelerated egg transport, as shown by a decrease in the number of ova present in the oviducts. In cyclic rats, intrabursal injection of 1 mg kg-1 of either N-monomethyl-L-arginine (L-NMMA) or N omega nitro-L-arginine methyl ester (L-NAME) elicited a 30% reduction in the number of ova present in the oviducts, whereas in pregnant animals, the same dose of L-NMMA produced a reduction of 40%. Simultaneous administration of the NO donor spermine NONOate (5 mg kg-1) completely reversed the effect of L-NMMA. Tubal motility was assessed by microsphere displacement analysis within the oviduct. Surrogate ova were transferred to the oviductal lumen at oestrus and 24 h later the effect of intraoviductal injection of 1 microgram L-NMMA or vehicle was assessed. The microspheres in the isthmus showed an oscillating motion, and periods in which movement was not detectable. However, L-NMMA treatment produced a 3.6-fold increase in the maximum instant velocities and a significant reduction in the resting periods of the microspheres compared with the control group (P &lt; 0.001). These results provide evidence that NO inhibition increases tubal motility that results in accelerated ovum transport, and indicate that NO could act as a paracrine signal between different layers of the oviductal wall, providing a role for endogenous NO in regulation of tubal function.

Effect of lysophosphatidic acid on the ovum transport in mouse oviducts

The effects of lysophosphatidic acid (LPA) on ovum transport in mouse oviducts were studied. When excised oviducts were incubated at 37°C under 5% CO 2 in humidified air for 24 hours, addition of LPA at 10 μm to the medium significantly accelerated the rate of ovum transport, and 1μM LPA slightly increased the ovum transport rate. These increases were not inhibited by 10 μM indomethacin, a cyclooxygense inhibitor, but were suppressed by 200 ng ml of pertussis toxin or 10 μM verapamil, a voltage-sensitive calcium channel blocker. These data suggested that LPA stimulates mouse ovum transport by contracting oviductual smooth muscle via a voltage-sensitive calcium channel mediated by a pertussis toxin-sensitive G-protein-linked receptor.

Investigation of ovum transport in the oviduct: the dynamics of oviductal fluids in domestic rabbits.

Ova are captured by the oviductal fimbria and rapidly transported to the ampullary-isthmic junction of the fallopian tube. Fertilized ova and oviductal fluids are then carried medially in the fallopian tube, while undergoing maturation in preparation for entering the uterine cavity, where nidation and further development take place. This movement of oviductal fluids was visualized in a rabbit model with human chorionic gonadotropin-induced ovulation, by injection of a contrast medium into the ampulla region of the oviduct. In the ampulla, the opaque medium was observed to oscillate at 0-85.4 mm/s. This medial transport of the fluid towards the uterus decreased to 0-9.6 mm/s in the isthmic portion of the tube. This decrease substantiates previous findings that the transport of material in the isthmic portion of the oviduct is more strongly under the control of ciliary action than under peristaltic activity.