Oviduct Contractions Research Articles

Inositol phospholipid hydrolysis may mediate the action of proctolin on insect visceral muscle

AbstractThe formation of inositol phosphates in response to the neuropeptide proctolin was studied in locust oviducts. Glycerophosphoinositol, inositol 1‐phosphate, inositol 1,4‐bisphosphate, and inositol 1,4,5‐trisphosphate were identified in the locust oviducts using anion‐exchange chromatography. Proctolin stimulated the release of inositol 1‐phosphate, inositol 1,4‐bisphosphate, and inositol 1,4,5‐trisphosphate during a 5‐min incubation. In the presence of lithium ions the effects of proctolin were enhanced, with elevations of 98%, 42%, and 45% of inositol 1‐phosphate, inositol 1,4‐bisphosphate, and inositol 1,4,5‐trisphosphate, respectively.Physiologically the effects of proctolin upon muscular contraction of locust oviducts were mimicked by the active phorbol ester, phorbol 12‐myristate 13‐acetate, and by the diacylglycerol analogue, 1‐oleoyl‐2‐acetylglycerol. The inactive phorbol ester, 12‐myristate 13‐acetate 4‐O‐methyl ether, was without effect. The effects of the active phorbol ester and the diacylglycerol analogue were calcium‐dependent requiring micromolar concentrations of calcium.The results indicate that the locust oviducts possess proctolin receptors that are linked to phosphatidylinositol metabolism and that inositol phospholipid hydrolysis may mediate the physiological action of proctolin.

Regulation of egg laying and in vitro oviductal contractions in Gryllus bimaculatus

Oviductal contractions and the control of oviposition were investigated in vivo and in vitro in Gryllus bimaculatus females. In vivo experiments showed that oviposition is controlled nervously by both the brain and the last abdominal ganglion, and that one or more neurohormones cause ovipositor movements and abdominal contractions. In vitro, the assay of nerve ganglia and corpora cardiaca extracts on the isolated oviduct showed that they markedly increase the frequency of oviductal contractions. However, the action of thoracic ganglia extracts varies according to a circadian cycle. This observation, combined with the finding that the effects of the corpora cardiaca differ from those of the brain, suggests that each of these organs contains distinct neurohormones. None of the neurotransmitters tested was as potent as brain or ganglia extracts, although octopamine, l-glutamate and proctolin do stimulate oviductal contractions at low concentrations.

Stimulatory effects of male accessory-gland extracts on the myogenicity and the adenylate cyclase activity of the oviduct of Locusta migratoria

The effects of male accessory-gland extracts on the myogenic contractions and the adenylate cyclase activity of the oviduct of Locusta migratoria have been examined. The extracts stimulated first the frequency and the amplitude, then the tonus of the oviduct contractions in dose-dependent and reversible ways. They also stimulated the adenylate cyclase activity of oviduct disrupted-cell preparations. Extracts of opalescent glands (one of the 15 male accessory glands) gave similar results with only a quantitative difference. The tonus response is probably independent of the adenylate cyclase activity because octopamine and forskolin did not mimic this effect, and also because phentolamine was unable to inhibit the effect. Frequency and mainly amplitude responses can be induced through an adenylate cyclase-dependent receptor as shown by the similitude of actions with octopamine and forskolin. However, since the effects on the adenylate cyclase activity of octopamine and the accessory-gland extracts were cumulative, we concluded that these compounds are acting on two discrete types of receptors. All these results suggest that male accessory-gland secretions directly act upon the oviduct, in one case through adenylate cyclase-dependent receptors.

Further Observations on Arginine Vasotocin-Induced Oviposition and Parturition in Lizards

Further Observations on Arginine Vasotocin-Induced Oviposition and Parturition in Lizards

In vivo recording of oviductal contractions in rabbits during the periovulatory period.

Muscular activity of the oviductal isthmus was recorded in intact awake rabbits with an extraluminal optoelectronic transducer. Telemetered data were collected continuously during the periovulatory period to relate changes in contraction frequency to oviductal transport function. Mean frequencies during estrus ranged from 11.7 to 18.7 contractions/min. Animals stimulated to ovulate either by luteinizing hormone (LH) or by mating showed equivalent responses. Within 2 h following the stimulus, the frequency increased rapidly and remained elevated more than 50% above the estrous control level for approximately 10 h. Thereafter, the frequency declined slowly to reach a second plateau, 30% below the control level, which was maintained throughout the 2nd and 3rd poststimulus days. Subsequently, the activity returned to the prestimulus level. The periods of elevated and depressed activity correspond closely in time to the periods of rapid preovulatory transport of sperm and slow postovulatory transport of ova through the isthmus, suggesting the possibility of regulation of gamete transport by the oviductal musculature.

Arginine vasotocin‐induced in vitro oviductal contractions in Anolis carolinensis: Effect of steroid hormone pretreatment in vivo

AbstractOvariectomized female Anolis carolinensis were treated for 14 days with one of the following regimens: (1) estradiol (1 μg/0.05 ml saline/day), (2) progesterone (10 μg/0.05 ml saline/day), or saline (0.05 ml/day). Oviducts then were removed surgically and placed in a bath containing Munsick's solution, to which was added either arginine vasotocin (30 ng/ml) or saline. Although saline produced no effects, AVT‐treated oviducts exhibited rhythmic contractions regardless of pretreatment regimen. Five parameters of the contractions measured were: (1) duration, (2) amplitude, (3) Strength (duration × amplitude), (4) frequency, and (5) rest. Each parameter then was analyzed using a 2 × 3 × 8 mixed, repeated measure design and analysis. Pretreatment with estradiol and progesterone significantly affected contraction strength, amplitude, and duration. Progesterone pretreatment produced oviductal contractions significantly stronger than saline pretreatment (p < 0. 001), whereas estradiol pretreatment produced significantly weaker contractions that saline pretreatment (p < 0.001). These findings are in contrast to those previously recorded for mammals and other reptiles in which estrogens support and progesterone inhibits uterine contractions. These data may suggest a unique adaptation of hormonal control of oviductal contraction in A. carolinensis to the alteration of oviposition during this lizard's reproductive cycle.

Stimulation of parturition in a viviparous lizard ( Sceloporus jarrovi) by arginine vasotocin

Pregnant, adult female Sceloporus jarrovi were randomly partitioned into three groups. The control subjects received a single intraperitoneal injection (0.1 ml) of 0.75% physiological saline ( N = 4), whereas the experimental animals received 0.02 μg AVT/0.1 ml saline ( N = 5) or 2.0 μg AVT/0.1 ml saline ( N = 5). Several dependent measures of parturition were obtained, including (1) initial contraction latency, measured as the duration from injection to first effective contraction, (2) parturition latency, or the time lapse between injection and first birth, and (3) interbirth duration, representing the period of time between individual births. Neither oviductal contractions nor parturition were observed in saline-treated females, whereas both concentrations of AVT induced parturition in all experimental subjects. No significant differences were indicated between the two AVT groups for initial contraction latency and parturition latency. Mean duration between individual births for the 2.0 and 0.02 μg AVT groups did not differ and were found to be similar to those reported for natural births.

Quantitative assessment of oxytocin-stimulated oviduct contractions of the ewe by optoelectronic measurements.

An optoelectronic instrument, developed to record the muscular activity of the oviduct was used to monitor the effects of oxytocin on oviductal contractions in intact ewes. The transducer consisted of one light emitting diode opposed by two phototransistors and their associated lead wires molded into a “C” shaped cuff in a clear orthodontic resin. The resulting optoelectronic transducer was attached extraluminally to the ampullary region of the oviduct with a cyanoacrylate tissue glue. Lead wires were exteriorized through the flank and connected to the external system electronics to record changes in the light transmittance (LT) resulting from contractions of the oviduct. Recordings from an in vitro experiment using simultaneous force and optoelectronic transducers confirmed that changes in oviduct contractile activity induced by oxytocin were accurately reflected in the optoelectronic transducer signal. Four ewes were instrumented to test how oxytocin treatment during the luteal phase altered the frequency of oviductal contractions. Twenty-four hours after implanting the cuff, logarithmically increasing doses of oxytocin were administered via jugular catheter at 5-hr intervals to each ewe. The ampullary contraction frequency before treatment ranged from 12 to 18 cycles per minute. This contraction frequency increased, and its amplitude decreased within the first min post-oxytocin injection. The mean of the maximum increase in the contraction frequency following injection was 1, 4, 7, 11, 20, 56, 58 and 71 cycles per min corresponding to injections of saline, .11, .33, 1, 3, 9, 27 and 81 USP units of oxytocin. A semi-log plot of the frequency change vs the oxytocin dose exhibited a typical sigmoid dose-response curve. These results illustrate the utility of the optoelectronic transducer as a tool for quantitatively assessing the effects of drugs on oviduct activity in intact unanesthetized animals.

Accelerated ovum transport in rabbits induced by endotoxin II. Changes in oviductal smooth muscle activity

Oviductal motility, measured with open-ended perfused catheters in anesthetized animals injected with human Chorionic Gonadotropin (hCG), is depressed 2 h following endotoxin injection and returns to control levels by 3 h after endotoxin injection. This decrease in motility is prevented by indomethacin. Endotoxin did not affect spontaneous or phenylephrine (PE)-induced contractions of oviduct when it was added to the bathing medium of in vitro tissues. Oviductal segments removed 2 h after endotoxin (26 h after hCG) showed electrical activity confined to the ampullary-isthmic-junction (AIJ), where ova were located; the dose-response curve for PE was shifted to the right and the maximum contraction was depressed. Activity of tissues removed 4 h after endotoxin more closely resembled control tissues except that the maximum contraction to PE was depressed, ova had passed out of the oviduct and a proovarian bias in the isthmus was not present. The response of the oviduct to prostaglandins (PGs) in vivo is critically dependent on the previous exposure to PGs. In endotoxin-treated animals PGE then PGF levels increase and the decrease in motility coincides with increased PGE levels, but accelerated ovum transport with the return of motility and activation of the isthmus.

Comparison of the effects of prostaglandins D 2, F 2α and E 1 on spontaneous contractions of rabbit oviduct

The effects of PGD 2, PGF 2α and PGE 1 were studied on the circular muscle of post-ovulatory rabbit oviducts in vitro . PGE 1 inhibited spontaneous contractile activity. Lower concentrations of PGD 2 and PGF 2α were stimulatory and higher concentrations were inhibitory. Since PGD 2 may be produced in the oviduct, any hypothesis concerning the role of prostaglandins in the control of oviductal motility and ovum transport should include PGD 2 as well as PGFs and PGEs.

New Concepts in Hormonal Control of Parturition1

Key factors in the control of parturition thus far identified have included: progesterone neurohypophyseal hormones fetal adrenal corticoids estrogens sympathomimetic amines and prostaglandins. The same sex steroids have different roles in birds reptiles and mammals. Neurohypophyseal hormones vasotocin and oxytocin can evoke a contractile response oviposition and/or parturition. The spontaneous contractile activity of the oviduct can be influenced by estrogen or progesterone by the time of the breeding cycle and by the stage of gestation. Calcium appears to be the major mediator of muscle action. Adenosine cyclic 35 monophosphate (cAMP) is a major intracellular messenger. Prostaglandin fulfills the role of oviduct contraction in all the mammalian species where it has been tested. Prostaglandin effects in muscle are not influenced as much by the sex hormones as are the neurohypophyseal hormones. Active contraction can be evoked at any stage of human gestation by prostaglandins and they are considered critical for normal delivery. Sympathomimetic amines have broad representation in phyletic development. The uterus responds to them by contracting or relaxing depending on the species gestational stage and other factors. The beta mimetic amines are not considered a major factor in animal parturition. Sex steroids may control the membrane receptors that allow the direct acting agents to affect the myometrial cells. Secondary regulators thus operate by altering the synthesis metabolism receptor availability or activity of primary regulators. Tertiary regulators occur in viviparous mammals and appear to control both primary and secondary regulators. They generally have a fetal source. Prostaglandin could be both a primary and tertiary regulator. Such a scheme accommodates known and as yet unknown hormone mechanisms and predicts exceptions.

Correlation between intraluminal pressure of the oviduct and the electrical activity of the longitudinal peritoneal muscle in the rabbit.

Correlations between the intraluminal pressure of the oviduct isthmu s and the electrical activity of the longitudinal peritoneal muscle surrounding the oviduct were studied in vivo in the rabbit. The electrical activity of the longitudinal peritoneal muscle was measured by implanted teflon-coated wire electrodes and the intraluminal pressure was measured by balloon-tipped catheters. A correlation between the spikes of electrical activity recorded in the peritoneal muscle and bursts of increased liminal pressure was found. The results suggest that the spontaneous increases in intraluminal pressure is the result of contractions of the longitudinal peritoneal muscle rather than the result of oviductal contractions in themselves.

Effect of vaginally administered 15(S)15-methyl-PGF2alpha on egg transport and fertility in rabbits.

The effects of vaginal suppositories containing 1.0 mg of 15[S]15-methy-PGF2alpha on oviductal motility, egg transport, and fertility were determined in rabbits. Suppository treatment caused a significant increase (P less than 0.02) in the amplitude of oviductal contractions, and a decrease in the frequency of contractractions (P less than 0.04). Altered oviductal motility persisted for an average of 2 hr after treatment. Treatment with 1, 2, or 3 suppositories at various times after ovulation caused a significant reduction in the number of eggs located in the oviducts (P less than 0.025). There was, however, a great deal of variation in egg recovery in treated animals (range 0 to 100%). Treatment of mated rabbits during the time of tubal egg transport caused a significant reduction in the number of Day-12 implants (P less than 0.05). The percentage of corpora lutea represented by Day-12 implants was similar to egg recovery rates in animals similarly treated. The treatment had no effect on fetal survival from Day 12 to 28 of pregnancy. The decrease in fertility caused by these vaginal suppositories is presumably due to the stimulatory effect on oviductal motility which accelerates tubal transport of the embryos into the uterus. Embryos that arrive in the uterus prematurely probably do not implant and degenerate or are expelled.

Sperm Transport and Distribution in the Reproductive Tract of the Female Rabbit After Intraperitoneal Insemination

Both live and dead spermatozoa were used to study the transport and distribution of sperm in the reporductive tract of 3 groups of rabbits. The female rabbits studied were: 1) rabbits in estrus and not treated, 2) rabbits injected with 25 IU of human chorionic gonadotrophin (HCG) 12 hours before intraperitoneal insemination, and 3) rabbits injected with HCG 96 hours before insemination. Upon autopsy, it was found that spermatozoa were transported in an abovarian and adovarian direction in the oviduct. Motile spermatozoa were more consistently recovered from the reproductive tract than immotile. Fewer spermatozoa were recovered from the reproductive tracts of pseudopregnant rabbits than rabbits in estrus or at ovulation. Sperm motility and oviduct contraction affect the pickup of spermatozoa by the fimbriae. Since most of the spermatozoa recovered from the oviduct were found in the ampulla, it is suggested that their abundance over those found in the isthmus was due to anatomical barriers in the oviduct created by the isthmus. Oviductal contractility is also seen to affect the distribution of sperm in the oviduct.

Utero-oviductal motility with emphasis on ova transport.

Utero-tubal motility in vivo has been observed in conscious animals by several methods. In women cyclic variations have been seen. As ovulation approaches the activity increases. In vitro motility was maximal in myometrial strips from estrous ewes intermediate in strips from ovariectomized ewes and least in strips taken during the luteal phase. It has been thought that estrogen stimulates and progesterone suppresses oviductal muscular contractility. This has been disproved. A relationship between the activity of the oviduct and of the uterus has not been shown in women. Experiments indicate that prostaglandins are involved in the regulation of the oviductal function and of the uterine musculature. Other possible effects of prostaglandins are thought to occur. In women oxytocin and vasopression exert their maximal responses in the utero-ovarian motility during the late luteal phase and during menstruation. Both epinephrine and norepinephrine have stimulatory effects on oviductal activity throughout the cycle but least during the luteal phase. The uterine musculature responds differently to the effects of epinephrine and norepinehprine being more relaxed under epinephrine. The pacemaker of oviductal contractions has been localized in a discrete area around the ampullary-isthmic junction. Uterine activity is myogenic. Myometrial pacemaker activity is not confined to a distinct anatomical area. Impulses are conducted through the uterine muscle in a wavelike pattern and are propagated equally in all directions. The mammalian oviduct is a dynamic structure. It is not a passive conduit for the gavetes. The progress of spermatozoa in 1 direction and the transport of ova in the opposite direction are primarily controlled by the coordinated action of peristaltic antiperistaltic and segmental waves of contraction. The stream of oviductal secretions and the rhythmic beat of cilia are also important. Oviductal and uterine smooth musculature are under the control of the secretions of the corpus luteum. The utero-tubal junction is a transitional zone. In women the intramural portion of the oviduct has a convoluted course and varies in length from 1 to 3.5 cm. It acts in concert with the uterus and the isthmic portion of the oviduct. The progressive movement of ova is temporarily arrested 1-2 cm from the uterus. Ova then pass rapidly through the utero-tubal junction. A timed delivery of the fertilized ovum is of critical significance for normal implantation. In some sterile dysmenorrheic women as isthmic spasm has been demonstrated and assumed to have caused the sterility. Contraceptive drugs profoundly affect the myometrial cycle by changing the regulatory system. IUDs have been shown to cause altered oviductal function.

Extraluminal recording of oviductal contractions in the unanesthetized rabbit.

Extraluminal recording of oviductal contractions in the unanesthetized rabbit.

The Mechanism of Ovulation and Oviposition in Aedes aegypti12

The general anatomy and histology of the female reproductive system and its innervation are described in detail. Contractions of the ampullae, lateral oviducts, and ovaries are rhythmic; they are basically independent of age, sexual and nutritional status, endocrine secretions, and nervous stimuli. The common oviduct does not contract. Ovulation cannot occur without complete maturation of the egg and rupturing of the follicular intima. Both ovulation and oviposition are solely due to the rhythmical contractions of the lateral oviducts and are essentially independent of the activities of the external genitalia. In the intact mosquito, however, the nervous system in some unknown manner initiates ovulation and oviposition, and coordinates both internal and external processes. The regulatory oviposition centers are located in the head and thorax.

Transport through the rabbit oviduct.

Longitudinal contractions of the rabbit oviduct do not change in amplitude or rate at different intervals after mating to 4 days, but they become greater in pregnancy and less in pseudopregnancy. Oil and India ink are spread in both directions by segmentation and pendular movement of the smooth muscle but they are arrested at 2–3 cm anterior to the tubo-uterine junction unless more than 0.1 ml is used. Paralysis of the muscle with nicotine prevents movement. When a plastic tube is inserted through the tubo-uterine junction, passage of ova past the critical zone is hastened. Ligature of the infundibular end of the oviduct causes distension, so that oviduct secretions must normally pass through the infundibulum and not into the uterus. This probably aids the transport of spermatazoa while ova are kept from escaping in this direction by the cilia and by the mucosal folds.