Drug-induced motility of sow (Sus scrofa) graafian follicles isolated during pre and post-ovulatory periods of the sex cycle.

The spontaneous as well as the drug-induced motility of sow graafian follicles during the early-preovulatory (E-preovulatory), late-preovulatory (L-preovulatory) and post-ovulatory stages of the sex cycle, were studied. Spontaneous motility was present only in 30.9% of the E-preovulatory and in 18.1% of the L-preovulatory, whereas none of the post-ovulatory follicles showed spontaneous contractions. All the quiescent preparations reacted, with a comparable enhancement of tension, to the addition of acetylcholine. On the other hand, norepinephrine (NE) elicited upon L-preovulatory and post-ovulatory follicles a significantly greater contractile response than over E-preovulatory preparations. The presence of MJ-1999 augmented clearly the positive influence of NE upon the contractile tension of E-preovulatory follicles, whereas cocaine, U-0521 or indomethacin failed to alter the reactivity towards NE in all the groups. The inotropic influence of prostaglandins were also explored over quiescent follicles. PGE1 diminished the basal tension of the three types of follicles, whereas PGF2-alpha produced the opposite effect. On the other hand, PGE2 enhanced the tonic tension of E and L-preovulatory preparations and reduced the basal tone of post-ovulatory follicles. The role of the spontaneous motility of smooth muscle fibers surrounding graafian follicles, as well as the effects of several autacoids and neurotransmitters prior and following ovulation are discussed in relation to their possible relevance for the ovulatory process.