Sheridan A. Halbert

Methods for studying oviductal physiology.

In studying oviductal physiology, it is important to sort out the complex interrelationships between muscle, cilia, nerves and secretory processes as they each of themselves, or in concert, effect gamete transport. In this review, a variety of physiological techniques and bioengineering approaches which have been used to monitor contractile and ciliary activity, are described and critically evaluated.

Hydrosalpinx: effect of oviductal dilatation on egg transport.

Ligation of the ovarian end of the oviduct was used to induce hydrosalpinges in rabbits and monkeys. This procedure resulted in an accumulation of clear serous fluid within the lumen and distention of the ampullary wall. The ampullary endosalpinx responded with a general flattening of the surface architecture, especially a decrease in the prominence of the longitudinal mucosal folds. However, this flattened epithelial surface showed normal ciliation. Two to five months after ligation, direct observations were made in vivo of luminal transport of cumulus egg masses and surrogates. These observations were followed by study in vitro of ciliary currents on the exposed luminal surface. The results demonstrated conclusively that tubal dilatation had no adverse effect on cilia-mediated ovum transport within the ampulla. The implication of these results in terms of tubal infertility is discussed.

Electron Microscopic Examination of the Rabbit Oviductal Ampulla Following Microsurgical End-to-End Anastomosis *†

The endosalpinx of both normal and microsurgically reconstructed ampullae in rabbit oviducts was examined by scanning and transmission electron microscopy following ovum transport studies. Tall, longitudinal mucosal folds ran continuously throughout the lumina of normal ampullae and were clearly interrupted at the incision site in the reconstructed oviducts. In both normal and surgically repaired tubes the endosalpinx was covered with long, slender cilia and bulbous processes of secretory cells with microvillous surfaces. Intracellular examination of these epithelial cells suggested no abnormal structure or function. These observations indicate that the epithelium on the severed ends of the endosalpinx healed completely within 1 month following ampullary anastomosis. Since no luminal obstruction was observed, the interruption and misalignment of the mucosal folds appear to be the cause of the impaired ciliary transport of cumulus masses observed in these oviducts. When species differences in tubal structure and function are considered, it appears likely that ampullary-ampullary anastomosis could hinder egg transport and fertility in women.

An Analysis of the Mechanisms of Egg Transport in the Ampulla of the Rabbit Oviduct

Ampullary transport of supravitally stained cumulus egg masses was studied in intact oviducts of anesthetized rabbits whose abdomens had been opened for observation. Following observations of normal t

In Vitro Contractile Activity of the Mesotubarium Superius from the Rabbit Oviduct in Various Endocrine States

We investigated the influence of estrogen on the contractile activity of smooth muscle in the nonpregnant female reproductive tract, using as a model isolated strips of mesotubarium superius (MTS) removed from the rabbit oviduct. We studied four physiologic states in which muscular activity was influenced to varying degrees by endogenous estrogen. Normal estrous (estrogen dominated) rabbits were used as controls. We observed decreased activity in MTS from rabbits chronically deprived of estrogen (60) days postovariectomy). However, a dramatic increase in activity occurred in response to acute withdrawal of ovarian function (12 hours postovariectomy). An increase in activity also occurred at the time of ovulation. We concluded that acute withdrawal of endogenous estrogen is a potent stimulus to reproductive smooth muscle in the female rabbit and that it might contribute to increased muscular activity at ovulation.

The effect of autonomic drugs on ureteric peristalsis: A canine in vivo study

SummaryAn in vivo canine model was developed in which the renal pelvis was perfused by a cannula nephrostomy and ureteric activity assessed by monitoring bolus volume and interperistaltic interval. The effect of autonomic drugs showed that the ureter contained α-adrenergic receptors which on stimulation caused an increase in ureteric contraction rate and a decrease in bolus volume. With β-adrenergic receptor stimulation, there was complete inhibition of ureteric peristalsis for a variable period and evidence is presented that the β-adrenergic receptors may be β1 rather than β2. Cholinergic stimulation of ureteric rate was observed, but seemed to be mediated indirectly via α-adrenergic receptors. No significant change was seen in ureteric activity with adrenergic blocking agents alone, suggesting that the physiological importance of these receptors in normal activity is questionable.

Function and Structure of the Rabbit Oviduct following Fimbriectomy. II. Proximal Ampullary Salpingostomy

Experiments were conducted in nine New Zealand White rabbits to determine the functional capacity of that part of the oviduct consisting of only the isthmus and proximal ampulla. The left fimbria and at least one-half of the adjoining ampulla were excised microsurgically and the remaining portion of the proximal ampulla was subjected to a cuff salpingostomy. Following a convalescence of 4 to 8 weeks and gonadotropin-induced ovulation, direct observations in vivo showed tht the modified oviduct was ineffective in transporting surrogate cumulus masses into the tubal lumen. Those surrogates that were accepted were in some cases regurgitated by contractions of the residual proximal ampulla. A subsequent in vitro search for ova proved that the modified oviducts were unsuccessful in retrieving ipsilaterally ovulated ova, whereas the contralateral control oviducts apprehended an average of 72% of those available. Scanning electron microscopy showed the everted mucosa of the proximal ampulla to be less richly endowed with cilia than that of the normal fimbria. This ovum capture appeared to be prevented by deficiencies in both the ciliary mechanism of the neofimbria and the ability of the remaining ampulla to retain the egg. This evidence indicates that the proximal ampulla is unsuitable for reconstruction of a functional fallopian tube.

The Effect of Glucagon and Diazoxide on the Normal and Obstructed Upper Urinary Tract

The effect of diazoxide and glucagon were studied on the freely draining upper urinary tract and after varying periods of obstruction in dogs. Without obstruction, diazoxide produced longer inactive periods than glucagon and recovery was associated with less retrograde activity. Following obstruction for 5--10 min, 6 and 24 h, diazoxide decreased renal pressure and the effect was greatest when the upper tract was obstructed for the shortest period. Glucagon also produced an overall reduction in pressure after 5--10 min and 6-hour periods of obstruction, but there was an initial rise in pressure after 5--10 min of obstruction. At 24 h there was an increase, but no overall decrease in pressure after glucagon. Diazoxide produced a greater fall in pressure after 5--10 min and 24 h of obstruction, and a faster fall in pressure after 5--10 min and 6 h of obstruction as compared to glucagon. Diazoxide may be a more effective therapeutic agent in the management of ureteral calculus disease than glucagon.

Egg Transport in the Rabbit Oviduct Following Ampullary Resection and Microsurgical End-to-End Anastomosis *

Surgical alteration of rabbit oviducts was employed to investigate the mechanisms of ovum transport. Resection of a 5- to 10-mm segment of midampulla was followed by microsurgical end-to-end anastomosis. One to two months later, direct observations were made, in situ, of ampullary egg transport. Stained cumulus masses were transported normally to the site of anastomosis: two-thirds of those studied were delayed at that point for an average of 2 1/2 minutes. Normal transport then resumed and continued to the ampullo-isthmic junction. In all but one instance, blockage of muscular activity with isoproterenol prevented transport beyond the anastomosis site, demonstrating the presence of an obstacle to ciliary transport. These studies reveal an important facilitative role for muscle in improving the reliability of ampullary egg transport. Considering species differences in egg transport mechanisms, it is suggested that ampullary-ampullary anastomosis in women might have a poor prognosis for re-establishing fertility.

Mechanically-induced hydrosalpinx: long-term oviductal dilatation does not impair ciliary transport function.

Long-term hydrosalpinges were mechanically induced in rabbits by ligation of the fimbriated end of the oviduct. The structure and function of these model hydrosalpinges were studied 28 to 52 weeks following ligation. This procedure caused a nonpurulent, clear serous fluid to accumulate within the lumen of the ampulla, which resulted in dilatation of the ampulla and thinning of the tubal wall. The intraluminal mucosal folds were attenuated in the expanded regions; however, normal ciliation was predominant throughout the endosalpinx. Two rabbits, one with a single distal tubal ligation and the other with double ampullary ligation, showed abnormal epithelium with distinct patches of flattened polygon-shaped, nonciliated cells. In vivo and in vitro observations of luminal transport of surrogate ova in cumulus showed that ciliary transport was not affected by the long-term gross distension of the ampullae. The authors conclude that long-term tubal dilatation by itself does not alter tubal morphology sufficiently to impair ovum transport function in the oviductal ampulla.