Cyclical Changes in Utero-Oviducal Motility in the Rabbit

Abstract

The phasic activities of utero-oviducal musculature are co-ordinated to accomplish successful gamete transport. In untreated rabbits, the oviducal musculature shows dramatic daily changes in contractility (Salomy & Harper, 1971). In oestrogen-treated rabbits, contractions are characterized by high frequency, small amplitude and irregular pattern (Mattos & Coutinho, 1971). This oestrogen-dominated pattern is observed with either high or moderate doses of the steroid (Greenwald, 1963). During the luteal phase, the oviducal musculature becomes increasingly active (Boling, 1971) in response to increasing progestagen concentrations. Maximal contractility of the myometrium occurs during the preovulatory phase, and a`m yometrial block' (Csapo, 1970) is established during the luteal phase.A chronological study of the characteristic motility patterns may provide a further understanding of their physiological implications. The purpose of this investigation was to study cyclical changes in the activity of musculature of the oviduct and uterus in the rabbit during the transport of gametes.Balloon-ended, fluid-filled, polyethylene catheters were inserted in the lumen of the ampulla and the uterus of fourteen adult New Zealand rabbits in oestrus. Pressure fluctuations were transmitted and recorded using pressure transducers, a carrier preamplifier and a polygraph. Motility patterns were recorded during oestrus and for the first 5 days post coitum (p.c.). Does were mated to fertile bucks 48 hr after the insertion of catheters.During oestrus, the oviducal contractions were characterized by high frequency, low amplitude, and a slight change in tonus, as indicated by the instability of the resting pressure (Text- fig. 1A); in three rabbits, however, this pattern was not observed and the contractions were irregular and variable (Table 1). Following copulation, a progressive increase in activity was noted and, by 6 hr p.c., the active oviducal motility was characterized by high frequency and amplitude of contractions and regularly repeated outbursts of increased tonus (Text-fig. IB). The activity was reduced at 24 hr p.c. (Text-fig. 1C) and, at 60 hr p.c., an alternating rhythm was associated with rapid and slow sets of contractions (Text- fig. ID). Rapid sets of contractions were abol¬ ished 72 hr p.c. (Text-fig. IE). The relatively infrequent contractions were predominant. A progressive slowing down in frequency and an increase in the

Relationship Between the Electrical Activity of the Oviduct and the Uterus of the Rabbit in Vivo

“…The third point is the role of the uterotubal junction in the cyclic changes of motility of the genital tract. As pointed out by Aref & Hafez (1973), the phasic activity of the oviduct and uterus must be co-ordinated to accomplish successful gamete transport. As shown by this study, the ampulla exhibits different patterns according to the hormonal status of the animal : sustained bursts of low fre¬ quency (4 to 10/hr) occur during the preovulatory phase and short regular bursts of high frequency (60 to 90/hr) are found after coitus.…”

“…They strongly influence the patterns of contraction. The high frequency of contractions in the oviduct seen under oestrogen dominance (Mattos & Coutinho, 1971) is damped during the luteal phase (Aref & Hafez, 1973) and also after injection of progesterone (Higgs & Moawad, 1974). Furthermore, oestrogen withdrawal after ovariectomy increases ampullary contractions (Boling & Blandau, 1971).…”

Methods for Studying Oviductal Physiology

“…While simultaneously observing ampullary egg transport and the muscle contractility of oviducts in the abdominal dish preparation, two types of muscle activity have been reported: (1) those that are noncoordinated and not effective in transport, and (2) those that are either propagated or show space-time coordination and are effective in transporting the cumulus masses. Obviously one most be able to distinguish between these two types of contractile activity when monitoring contractions in intact animals, if such data are to be meaningfully evaluated in terms of transport function.…”